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Saturday, December 07, 2013

XCOM: Optimal character build or How to design skill trees

XCOM: Enemy Unknown is an amazing game, and this post is about how to choose optimal skill tree for various character classes in XCOM, but really it's just using that as a game design exercise. I'll be explaining what they did right and what they did wrong in designing skill trees, and then I'll summarize design points at the end of the point. It's just much easier to discuss this with a concrete example than on purely theoretical terms.

XCOM character progression

First, the basics in case you never played it. You get a bunch of 0xp soldiers, who don't even have character classes. Then as they get XP they get levels, and on each level they get HP, Aim, and Will bonuses, plus one skill, either mandatory or one of two to choose from.
  • Rookie - no class
  • Squaddie - character gets their randomly assigned class, one class-defining skill
  • Corporal - two skills to choose from
  • Sergeant - two skills to choose from
  • Lieutenant - two skills to choose from
  • Captain - two skills to choose from
  • Major - one skill
  • Colonel - two skills to choose from
All levels also get attribute bonuses depending on class, and they're a bit higher on squaddie and colonel than on other levels.

Even before seeing individual class trees, there's a lot of very interesting design going on here.

Random classes

First - you can't choose class your rookies are going to get, so pushes the player towards a balanced team. It's even more interesting, since classes are random with same chances, except your first four rookies will always all get different classes (if it was left completely up to chance, you'd most likely get some duplicates only 9.375% would be all-different).

Later in the game if you really want to have all-Heavy team you definitely can - either by hiring and training a lot of rookies until you get all the Heavies, or buying an officer school upgrade that makes all new recruits start at squaddie (with a class you want already).

But early game the path of least resistance most new players will take is a balanced team - which happens to be pretty decent strategy (not obvious, in a lot of strategy games spamming one or two unit types is optimal, and some are clearly awful), and get the player to enjoy more game elements than if they had full choice.

This random assignment can also increase frustration. If your only soldier of a class you need gets killed or wounded (and will require long hospital stay), you won't have any replacement easily available. You have ways to deal with this frustration - by training more rookies, or investing in Officers Training School, or going for missions where you get a higher level soldier as a reward, and slightly unbalanced team can still deal with most missions - but this random assignment just keeps on giving.

Fortunately they didn't overdo it - since there are only 4 classes and you have enough outs, you'll eventually be able to get the kind of squad you want. Random game elements are a

Skill trees

Another really neat design gem is with xp levels. Some levels are much more valuable than others - especially getting a Squaddie matters since then the soldier gets their class - and then depending on class different levels might have more or less important skills to choose from. Soldiers mostly get xp for participating in missions and killing aliens - and the way it's tweaked is that one mission participation (60xp) plus one alien killed (30xp, more for some high level aliens) is exactly the amount (90xp) needed to get that first promotion. This makes it really important to get rookies on the front lines, not just keep them behind farming mission participation xp while high level soldiers do all the work - but even without much luck all rookies will get their promotion on the second mission.

And there's a reason why some levels don't give you a choice. Some skills are class-defining - you have to pick them, or other skills dependent on them won't work (see Heavy class for details of that). And some skills are basically must-haves - so powerful it would be stupid to take anything else over them. Unfortunately here XCOM doesn't do a very good job (see Sniper class for details).


I feel Sniper has by far the worst designed skill tree of all classes, so let's start with it.

The difference between Sniper and other classes is that Sniper uses Sniper Rifle (or one of its upgrades based on alien technology) and can't fire it after moving. They can still fire a pistol, but that's a pretty miserable choice.

Skills for the first two levels are:
  • Squaddie - Headshot - fires shot with +30% critical hit and extra damage, 2 turn cooldown
  • Corporal - Snap Shot - can fire after moving with -20 aim penalty
  • Corporal - Squadsight - can fire at anything any ally sees (if there are no walls in the way)
This is just awful. Headshot is a nice to have, not a big deal, so it shouldn't go into mandatory slot.

Squadsight on the other hand is absolutely critical for any Sniper - since you can't shoot anything after moving and you are relatively weak, as a Sniper you should stay behind on high grounds with unblocked view of most of the battlefield and shoot aliens the rest of your squad finds.

Now Snap Shot would be interesting choice, but since Squadsight is a must have, Snap Shot never sees any action! What's worse - Squadsight and Snap Shot have interesting interactions. Sniper with both could move to flank a newly discovered alien, and then shoot it from a direction where they are not covered (low cover gives -20, high cover -40 to aim, so it might be worth Snap Shot penalty - and shooting alien completely in the open also gives huge critical hit %). But of course they're mutually exclusive so that never happens.

What this trees should instead look like is:
  • Squaddie - Squadsight - it's a must-have skill and a class-defining ability
  • Corporal - Snap Shot - nice to have
  • Corporal - Headshot - nice to have (or even more it much further down the skill tree, and put something else here)
In Enemy Within they reduced Snap Shot penalty and nerfed Squadsight a bit - but that still doesn't change the fundamental fact that Squadsight is still a must-have. Reordering these skills would be the only right thing to do, not tweaking stats.

And on top of all the problems with this - Squaddie Sniper with neither Squadsight nor Snap Shot is usually weaker than Rookie in a fight, since they need to stay close to aliens, but can't move then shoot to flank them while staying covered.

Anyway, let's pretend close combat Sniper (Snap Shot instead of Squadsight) is a thing in further discussion, since the skill tree was clearly designed with this assumption in mind, even though that never actually happens in real games.

The tree doesn't get any better later on:
  • Sergeant - Gunslinger - +2 bonus with pistols
  • Sergeant - Damn Good Ground - +10 aim and +10 defence against enemies at lower elevation, in addition to the usual elevation bonuses
Gunslinger is just really awkward here. If you go for Squadsight sniper as you should, you will find yourself using pistols in desperate situations sometimes (when a wall blocks your shot, and someone absolutely has to shoot the enemy this turn), but such situations are hopefully rare, while you'll be at high elevation most of the time. So it's a weak bonus vs strong bonus.

And even if you go for Snap Shot Sniper for some crazy reason - Gunslinger just does almost nothing since you can shoot your sniper rifle after moving just fine. And Damn Good Ground also does almost nothing since you'll mostly be facing nearby aliens at similar elevation. So it's very weak bonus vs weak bonus.

Either way, Gunslinger is always a bad pick.
  • Lieutenant - Disabling Shot - can fire a shot that causes target's primary weapon to malfunction until reloaded, but can't critical hit, 2 turns cooldown.  
  • Lieutenant - Battle Scanner - can throw scanning device that extends your vision for 2 turns, 2 uses per battle
Disabling Shot is just fairly weak - Snipers have high chance of critical hits against most aliens, and if you hit something you usually want to finish it same turn, not let it wander around and fire. There are some aliens who can't be killed in one shot, but this only affects primary weapon, and such aliens often have secondary weapons like grenades or melee attacks. Overall, a very weak skill.

For Squadsight Sniper you usually want to stay behind in safe elevated position, so you can't throw a battle scanner as far as you'd like. For Snap Shot Sniper, I don't even know if they could shoot at aliens revealed by battle scanner since they can't see them directly.

Battle scanners would be awesome for your close combat troops - since you know where aliens are, but they can't see you, why not ambush them? Except that won't really work since the moment you move within their range aliens get a free move to run to cover.

So maybe this should be redesigned by moving battle scanners to Support class instead, and making aliens seen this way not able to run for cover when triggered? For now even awkward battle scanners are still a lot better than nearly useless disabling shot.
  • Captain - Executioner - +10 aim against targets with less than 50% health
  • Captain - Opportunist - eliminates aim penalty for overwatch shots, and allows them to cause critical hits
This is probably the closest Sniper gets to actual skill choice, everything else being autopick. I'd say Opportunist is significantly stronger than Executioner, but Executioner is still a very nice bonus, if it was somewhere else. If this bonus was +20 aim or +10 aim and +10% critical hit, that would be a serious consideration.
  • Major - Low Profile - makes partial cover count as full
And this gets to be a forced pick? For a Squadsight Sniper this is fairly close to completely worthless. Your cover is being too far behind for aliens to be able to see you - and if they somehow ambushed you, you might just as easily have no cover whatsoever rather than partial cover.

For Snap Shot Snipers I can imagine this having some value, but not terribly much.

But you know for whom this bonus would be absolutely awesome? Assault class. Or any class other than Sniper.
  • Colonel - In The Zone - killing a flanked or uncovered target with sniper rifle does not cost an action
  • Colonel - Double Tap - can use both actions for shooting (including Heatshot and Disabling Shot), 1 turn cooldown
This is a Double Tap autopick, but for interesting reasons. Double Tap is a high reward low variance pick - you get to shoot 3 times / 2 turns instead of 2 times / 2 turns - greatly increasing your damage output no matter what.

In The Zone sounds like it could potentially shoot a lot more times than two, but this will rarely happen. Triggered aliens run straight to cover, and they tend to stay in cover - and you can't move to flank them. Melee aliens tend to avoid cover, but they tend to be hard to kill in one shot.

There are some uses - if there's a pack of multiple aliens one of your soldiers could throw a grenade at them, weakening them and destroying their cover. Then an In The Zone Sniper could finish them all off without using an action. I'm sure this happened sometimes, but as a player you should generally go for solid low variance choices (Double Tap) over choices which can occasionally be amazing but most of the time do nothing (In The Zone).

Now this isn't the worst part of the tree, since many players find high variance exciting - check "Timmy" player archetype in this article.


For a much better design let's take a look at Heavy.
  • Squaddie - Fire Rocket - fires a rocket using rocket launcher, cannot be used after moving, can be used once per battle
This is what mandatory skills should be like. Heavies have rocket launcher as a class characteristic, and many skills further down the road enhance either rocket launcher, or all area effects (and that's the only one you have here).
  • Corporal - Bullet Swarm - can use both actions to fire primary weapon
  • Corporal - Holo-Targeting - shooting at or suppressing enemy gives allies +10 aim against that enemy
Anything that doubles damage output is great, especially with no cooldown. The problem here is how fast you'll run out of ammo here. So it looks like they're both viable choices. But once you perform a Muton autopsy and get Ammo Conservation in a Foundry, your ammo will double, and this problem will go away, moving bullet swarm from about as good as Holo-Targeting to way better.
  • Sergeant - Shredder Rocket - fire a rocket that causes all enemies to take +33% damage from all sources for next 4 turns, but has weaker blast
  • Sergeant - Suppression - special shot that makes target suffer -30 aim, and grants free reaction fire against it (and also uses a lot of ammunition)
So many interesting things about this level. Suppression is the only ability that's available for multiple classes - Support Lieutenants also get it - and it's mostly useful for trying to capture aliens. In case you never tried it, the way it usually works is that your Heavy will suppress an alien, your Assaults (with Lightning Reflexes and maybe Resilience to protect against enemy fire) or Supports (with Sprinter for faster movement) will move towards it, and then maybe a Support will throw a Smoke Grenade to give your approaching and exposed soldiers some extra cover. Suppressed alien is likely to just stay under cover and often doesn't even try shooting, since AI prefers to save ammo rather than try shots with very low chance of succeeding.

And Shredder Rocket ability shows why Fire Rocket had to be mandatory. If Fire Rocket was optional, then if you didn't take it then, you couldn't take Shredder Rocket now.

Overall, Suppression is much better here. It's extremely useful for capturing aliens alive, it's somewhat useful in regular battle, and its main downside of going though a lot of ammo goes away with Ammo Conservation. But once you've captured all the aliens you'll ever want, Shredder Rocket is a serious consideration.
  • Lieutenant - HEAT Ammo - +100% damage against robots (nerfed to +50% in Enemy Within)
  • Lieutenant - Rapid Reaction - second reaction shot on overwatch if first one was a hit
Since most of your nastiest enemies are robots - HEAT Ammo is a really really good choice. Interestingly it also combos with a rocket not just primary weapon. After the nerf it's not as clear what's the better choice.

Rapid Reaction is not as good as it sounds early game, since Heavies go through a lot of ammo, and if 
you don't have enough ammo to shoot twice it won't work. Late game you'll have Ammo Conservation, but then you'll also have Cyberdisks and Sectopods trying to murder you.

HEAT Ammo was an interesting design as a safety valve. Balancing everything about the game is pretty much impossible, but you can put some elements like that in it instead. If robotic aliens end up being too powerful, players will pick HEAT Ammo more often making robots less menacing. On the other hand if robotic aliens end up being relatively weak (relative to what player has at that point of the game, other aliens etc.), players will tend to pick Rapid Reaction, and that will make robots stronger in relative terms.

Since robots turned out to be really powerful, HEAT ammo is the way to go.
  • Captain - Grenadier - can carry 2nd grenade in inventory slot
  • Captain - Danger Zone - increases area of effect of rocket attacks and suppression by 2 tiles
From design point of view Grenadier requires specific inventory item to be useful - and that means you won't be carrying any of the alternatives like SCOPE, or Chitin Plating. How good it is depends on how good you think grenades are, and that very strongly depends on difficulty level, aliens you face at that point of the game etc. 

Danger Zone depends on having either rockets (which are mandatory) or suppression (which is a very good pick), so it has synergies with both. I'd usually prefer Danger Zone and SCOPEs on heavies over Grenadier and grenades, but neither choice is an autopick.
  • Major - Will to Survive - reduces normal damage taken by 2 if in cover and not flanked
This is an amazingly useful skill, and I'm happy they made that mandatory. It's a bit funny whenever late game you face early alien types (like in some council missions which occur in random order). Aliens can then hit your Heavy as many times they want and do precisely 0 damage. Unfortunately when they miss they can destroy Heavy's cover, so missing alien is worse than a hitting one.
  • Colonel - Rocketeer - 1 additional rocket per battle
  • Colonel - Mayhem - additional damage for suppression and all area-effects
This shows one thing I really dislike about XCOM. Unlikely most other games XCOM doesn't show you research tree, possible future enemies, possible skills picks past current level etc. This makes sense from story point of view - at least the first time you play, the second time not so much - but it makes it very frustrating to play optimally.

Rocketeer synergizes very nicely with Shredder Rocket, HEAT Ammo, and Danger Zone - but you have to choose those early skills before the game reveals that this late skill exists.

Mayhem is nice, but one thing it synergizes most with is, well, Rocketeer. That is not a great design.

Value of rocket skills (HEAT Ammo, Danger Zone, Rocketeer, and Shredder Rocket too - but that last one is not as great) depends primarily on you having Slingshot DLC installed or not. WTF you're asking? All weapon types can be upgraded, but the only way to upgrade rocket launcher (to something ridiculously overpowered) is to capture an alien battleship and research Fusion Core.  The problem is that without Slingshot DLC you won't see Battleships until very late in the game - in fact you're more likely than not to finish the game before any Battleship mission, since they have the same prerequisite (upgraded aircraft). But with the Slingshot DLC you can capture one quite early, making your Heavies completely overpowered mid game. Either way, I'd pick Rocketeer.

Overall, I'd say Heavy's skill tree is quite well designed, and the only changes I'd make would be some rebalancing. The choice to hide skill tree is probably bad for mechanics, but it makes sense from storyline point of view.

And it might be a good idea to add some mid-game rocket launcher upgrade, since overpowered DLCs are not good for any game.


Assaults are also pretty nicely designed.
  • Squaddie - Run & Gun - allows firing or using overwatch after using both actions for moves, 2 turn cooldown.
This is a class-defining ability for Assaults, and it's extremely good, so it's good that it's mandatory.
  • Corporal - Tactical Sense - +5 defence per enemy is sight (max +20)
  • Corporal - Aggression - +10% critical hit chance per enemy in sight (max +30%)
Both of these are relatively minor bonuses, and I'd normally pick Tactical Sense since when there are enough aliens to worry about them your priority is probably not getting killed.
  • Sergeant - Lightning Reflexes - first reaction shot against the unit always misses
  • Sergeant - Close and Personal - +30% critical shot chance against adjacent targets, bonus declines with distance
Lightning Reflexes is a much better pick since it helps the entire team. You can run in front of overwatching alien with your Assault - possibly Run & Gunning quite far - and the alien will try to shoot and miss, making the movement safe for the entire team. It doesn't work that great if there are multiple aliens on overwatch close to each other.

Close and Personal is a nice bonus for situations where you're already winning and it's safe to get very close to the alien, but in more difficult situations you just don't want to do that.
  • Lieutenant - Flush - fires a shot that causes enemy to run out of cover, it's easier to hit but causes less damage
  • Lieutenant - Rapid Fire - can fire two shots against single target with -15 aim penalty
This is not even close. Flush might or might not be useful sometimes, but Rapid Fire is a must-have since it pretty much doubles your soldier's firepower - and actually increases hit chance since you have two chances to hit not one. Higher ammo use is a concern, but Assaults don't go through their ammo as quickly as Heavies, and you'll get Ammo Conservation eventually.

3 out of 4 classes have some way to shoot twice. Rapid Fire has benefit of taking just one action (unlike Bullet Swarm and Double Tap), so you can fire and shoot twice. With Run&Gun and Rapid Fire you even get to move twice and shoot twice in just one turn. What's better - unlike Double Tap, Rapid fire has no cooldown, and unlike Bullet Swarm Assaults don't run out of ammo that fast. It's pretty amazing. There's rarely any reason to use regular fire once you get Rapid Fire.
  • Captain - Close Combat Specialist - free reaction shot against any enemy which moves within 4 tiles, does not depend on overwatch
  • Captain - Bring 'Em On - 1 damage to critical hits for each enemy the squad can see (up to 5)
Assault will usually be closest to the enemy of all your soldiers, and Close Combat Specialist can fire multiple times a turn, so it's potentially extremely powerful. Bring 'Em On on the other hand is pretty underwhelming.

The only downside of Close Combat Specialist is that there's no way to disable it, so sometimes you'll kill an alien you were hoping to capture. That's a risk I'm willing to live with.
  • Major - Extra Conditioning - health bonus depending on type of armor equipped
  • Colonel - Resilience - immunity to critical hits
  • Colonel - Killer Instinct - activating Run & Gun gives +50% critical damage for the rest of turn
Extra Conditioning is sure nice, but it sounds like something Heavy should be getting. There are good reasons to give Assaults medium armor with high mobility like Skeleton Armor or Ghost Armor rather than heaviest armor possible.

Resilience would be useful on all classes, but Assaults need it the most since they're taking most risk.

From design point of view I'd make Resilience a mandatory pick, and make Colonel level choose between Extra Conditioning (if you want a more heavy Assault) or Killer Instinct (if you want a more mobile Assault). Still, it's a decently designed skill tree with a bit extra rebalancing.


Support class has a very different skill tree - either you go for Field Medic and pick all medic-related abilities, or don't and pick all overwatch/suppression related ones instead. Because of how much synergy there is between medic abilities, it's usually a bad idea to mix&match.

Support also has many abilities that help with capturing aliens, but there are some anti-synergies here.
  • Squaddie - Smoke Grenade - can throw smoke grenade that gives +20 defence bonus to all units under it, lasts through enemy turn
The bonus isn't that big, but it can sometimes save your soldiers' lives.
  • Corporal - Sprinter - can move 3 additional tiles per move
  • Corporal - Covering Fire - allows reaction shots to trigger on enemy attacks, not just movement
Sprinter is useful for many things - for medic, for throwing smoke grenades, for throwing regular grenades, to get to cover or flanking position etc. It's like a smaller version of Run&Gun with no cooldown.

A major downside is that Supports unlike Assaults can't get Lightning Reflexes, so they're totally vulnerable to aliens on overwatch, but they have to run a lot, something Snipers (who stay behind and shoot) and Heavies (who stay in one play and keep shooting until everything dies) don't have to worry about that much.

Covering Fire synergizes with Sentinel later, but if you're going for medic build, Sprinter is a must.
  • Sergeant - Field Medic - can use medkits 3 times per battle rather than just 1
  • Sergeant - Smoke and Mirrors - can use smoke grenades 2 times per battle (3 in Enemy Within) rather than 1
It's very risky not to have Field Medic Support soldier on your team, and that's mandatory choice for such character. You don't really need 2 Field Medics, so you could make a non-Medic Support with Smoke and Mirrors, but one extra grenade is just very weak, so non-Medic Support is pretty underwhelming.

And there are so many anti-synergies here. For capturing aliens sprinter and smoke grenades are both awesome, but one soldier can't both dash and use a smoke grenade on themselves. For non-Medic Support extra smoke grenades are nice - but then they can't use overwatch.

Just like Snap Shot Sniper, I'm not convinced non-Field Medic Support is really good for much.
  • Lieutenant - Revive - critically wounded soldiers recover to 33% of max health rather than just stabilizing
  • Lieutenant - Rifle Suppression - special shot that makes target suffer -30 aim, and grants free reaction fire against it
Revive makes no sense to take unless you're going for a Medic. For Medic it's somewhat underwhelming, since critically wounded soldiers happen relatively rarely (usually they either die, or survive), and one or two times a campaign it happens those few extra points probably won't make a huge difference. Rifle Suppression is just as useful as Heavy's Suppression, so I'd probably go for it, unless you see far more critical wounds than I do.

By the way this is another anti-synergy, since Rifle Suppression is another awesome skill for capturing aliens, but you can't really mix it with Smoke Grenades, or Sprinter. 
  • Captain - Dense Smoke - smoke grenades give extra +20 defence (+40 total) and have increased area of effect
  • Captain - Combat Drugs - smoke grenades give extra +20 will and +10% critical hit chance
I'd just go for Dense Smoke, since there are very few psionic aliens outside very narrow areas like UFO's command bridges, and there you just want maximum firepower, not any extra defence
  • Major - Deep Pockets - additional item slot in inventory (in Enemy Within instead additional use for each single use item)
This is a really nice skill for Field Medic, since slot one gets a medkit - and unfortunately you can't carry two medkits even with this skill. For second slot you can carry Arc Thrower, or grenades, or SCOPE, or whatever you want. That was actually a really nice synergy for capturing aliens, since Sprinter works well with both Arc Thrower and with medkit.

I don't feel that great about Enemy Within replacement bonus.
  • Colonel - Savior - medkits restore 4 more health per use
  • Colonel - Sentinel - two reaction shops during overwatch instead of one
All skills lead to either of these builds. It makes little sense to make a Savior without Field Medic and Sprinter, and it makes little sense to take Sentinel without Covering Fire, Riffle Suppression, and probably Smoke and Mirrors.  

From design point of view there are two subclasses for Support class, and mixing abilities is awkward. Support has by far the least firepower of all classes, so it's difficult to design it well - most people will take one Support Field Medic, and won't even bother with the Sentinel Build since low firepower makes it less useful, and harder to get xp for.

Covering Fire and Sentinel might be better on a Sniper instead, and Battle Scanner on the Support perhaps? Sprinter for that matter would synergize amazingly well with Assault's Lighting Reflexes and Run&Gun. Maybe Flush and Grenadier for the Support instead? It feels like rearranging skill trees could result in something much more interesting and balanced.

How to design skill trees

Here's a summary:
  • Randomness is a very powerful game design element, but don't overdo it.
  • Show whole skill trees, not just currently available portion, so player can look for synergies (problems with Rocketeer, Savior/Sentinel)
  • Not everything has to be balanced. Within reason, it's good when player can figure out that some abilities are more powerful than others - but it's not great when half of abilities never see any use. 
  • Avoid giving the player a choice between a must-have skill and a nice-to-have skill (Squadsight vs Snap Shot).
  • If two skills have interesting synergy, do not make them mutually exclusive (Squadsight + Snapshot).
  • If skills have anti-synergy, put them on separate classes. (mostly done right)
  • Don't make "upgrades" that make the character worse (like Squaddie Sniper).
  • Give player options to deal with potentially unbalanced game elements. At best they won't need them. (like HEAT Ammo).
  • If a skill is necessary for other skills, make it impossible to pick those other skills without picking the prerequisite (Fire Rocket and other rocket-related skills)
  • Some players like high variance game elements, others prefer solid low variance (In The Zone vs Double Tap)

Enemy Within update

This post talks about the base game XCOM: Enemy Unknown. Expansion pack Enemy Within changes a bunch of things, so it actually changes some recommendations. Two important things are gene mods and the now about 3x more powerful Sectopods.

In the base game Squadsight was way better than Snap Shot. It wasn't even close, total no-brainer. So what changes in the expansion after Squadsight gets nerfed and Snap Shot improved? The gulf between them becomes even more ridiculous! From being merely overpowered, the supposedly nerfed Squadsight is now completely and totally broken.

First, you get two neat synergistic gene mods designed for Squadsight - very cheap Depth Perception (+5 aim +5 critical chance if at height advantage) and somewhat more expensive Muscle Fiber Density (can just like thin men - basically somewhat better grapling hooks). That pretty much counters the nerf on its own.

But it gets better. You get Mimetic Skin gene mod, which you can use to make your soldiers pretty much invisible (if they stay in cover and don't shoot - they can use some abilities) - but your Squadsight sniper can still shoot them just fine. Aliens will trigger when shot, but since they see neither your invisible soldier (who didn't shoot) nor your sniper (who's beyond their range of sight), they're completely helpless. So in theory it would be possible to clean up most maps with one invisible soldier, and one low-level Squadsight sniper. Except it doesn't work on Chryssalids, and there are a few maps where you're against timer or have some objective other than surviving, so it's not always an autowin, but pretty close.

And did I mention that Mimetic Skin is pretty much free, since your investment will repay itself immediately since with just 1 or 2 invisible soldiers you can clean up all meld canisters on all maps? There are diminishing returns of course.

All this also makes In The Zone better, since you get the first sniper shot before aliens can run for covers, so now it's a reasonable pick over Double Tap. I'd still take Double Tap because it helps with Sectopods so much, but it's close enough.

One recommendation for Enemy Unknown which I'd now reverse for Enemy Within is Disabling Shot vs Battle Scanner. Battle scanner was always awkward on the Sniper, and you'll be getting something way better with your invisible soldier fairly early, so it becomes a dead pick. On the other hand Sectopods get a lot more powerful, and you won't be able to just double tap critical them and finish with a HEAT rocket like you used to, so Disabling Shot on them is pretty helpful. It's also not completely unreasonable to Disabling Shot your mind controlled soldiers, but then it doesn't happen all that much thanks to rampant invisibility.

All other recommendations still stand.


Anonymous said...

In EW, the sniper skill tree so much more better - the penalty for snapshot is only -10, and squadsight can no longer crit without headshot if the sniper itself is not in sight of the target.

Also, you VASTLY underestimate In the zone; the bonus procs for enemies that do not utilize cover too, such as drones, chrysalids, mechtoids and all flying enemies.

Disabling shot is also very useful, in cases where you need to bypass a sectopod overwatch, or disable the weapon of a mind-controlled soldier.

Anonymous said...

I agree with original boster and the commenter above. There are definetely perks that could have been rearranged in a better way.

For this reason training roulette is so fun in EW because it allows you to get some potentially interesting synergies.

Opportunist with any other overwatch perk is amazing. It looks like being able to crit on overwatch, regards moving enemies as exposed, which gives you 50% crit chance. Rapid reaction or sentinel will make your overwatch absolute killers. I got this on my heavy, it was amazing.

I think the entire concept behind the smoke grenade is getting underwhelming. EW has brought us ghost grenades, flashbangs. Both these do a similar / better job than smoke grenades. Later in the game when you get the psionic shield, you are even stronger. It needs something extra. EU has the aim bonus on smoke grenadeds with combat drugs. EW removed it and thus made it less useful.

Do not underestimate Bring'em on, i got this thing through training rouletter early on my soldiers and it is very powerful. The game gives you plenty of chances to improve your crit chance (reaper rounds, scope, flanking, removing cover, aggression perk, headshot skill), and bring em can be put to great use.

taw said...

Anonymous: I feel that the next time I play, it will probably be with training roulette and other second wave options (unless I just go on and manually mod the tree).

The whole post is really mostly about EU, not EW. EW complicated the system a lot more with gene mods etc. - only half the skills are dependent on class now. It made game fun for another few campaign, but it really has issues with balance.

Anonymous said...

The sniper skill tree looks only badly designed when you are leveling your first sniper and want him to be the perfect static tower sniper.

If you have others snipers in your team and need them to be more versatile, options like snipe shot or gunslinger become necessary.

taw said...

Anonymous: But what do you get for dropping squadsight? Basically an assault with lower firepower, low survivability, and lower chance to hit (higher aim, but since you have 1 shot/turn not 2/turn like assault or heavy, chance that at least one of them hits is lower), and no supporting abilities like support's medic, assault's lighting reflexes, or heavy's suppression/holo targeting.

If snapshot snipers had at least limited squadsight (gunners in Long War mod have this at visual range plus 5 tiles), or if squadsight snipers had some serious synergistic abilities other classes do, instead of only providing damage, that might be worth considering, but without either it's just really extremely low power option.

Anonymous said...

In enemy within with "not created equally" and hidden "potential" snapshot snipers destroy. My snapshot snipers have 118-120 aim without scopes. Disabling shot completely removes the threat from mechtoids, sectopods, cyberdisks...and in contrast to squadsight snipers they can move and land that disabling shot in a critical moment. In the zone or double tap are both viable builds for snap shot snipers. How can you discount the ability to have full cover anywhere they move? Excellent defensive flexibility in how you position your squad...and they don't have 1 shot/turn they often have 2 shots/turn (or more with in the zone) with a high damage weapon (that does more damage with headshot). My primary snapshot sniper has 100 kills in 30 missions.

I never used snap shot snipers in Enemy Unknown (squad sight was far better).

Anonymous said...

I find heavy builds to be not that great myself. For me, bullet swarm >>> holotargeting. +10 means less and less and your soldiers level up. For holotargeting to have maximum value your heavy needs to be 1st to shoot (constraining your choice of actions), if the heavy hits and kills the target then the holotargeting becomes meaningless, and you don't even know if the +10 holotargeting was the reason your team hits the target. The opportunity cost of not selecting bullet swarm is too high - it provides too much flexibility of action and can save the day when surrounded.

Rapid Reaction has almost no value in practice.

If suppression+danger zone is chosen and then mayhem is selected then your heavy has a SINGLE rocket. The only unique quality the heavy has is rockets and the AOE/damge with now I have only 1 rocket and a tiny bit of damage on suppression with an AOE effect that might come into play a couple times/entire playthrough unless you use ghost armor to contrive situations (and who that point the game is won). Poor aim heavy with a single rocket with a suppression ability that matters less and less as the game goes on = lame.

Rocketeer >> Mayhem

Suppression vs Shredder and Danger Zone vs Grenadier (Enemy Within with the upgraded grenade damage, 2 item slots with tactical rigging, and more grenade types - ghost, flashbang - grenadier becomes more viable). In Enemy Unknown, danger zone was the only choice.

In practice I find heavy builds boring because unless you bring multiple heavies (and I only bring 1) then this build is the only build:

Bullet Swarm
Shredder (sometimes suppression)
Danger Zone (sometimes Grenadier/Enemy within)
Will to Survive

Pax Empyrean said...

Years old blog post, but whatever. It's fun to see a detailed analysis of the design decisions behind the classes and then look at my own decisions when overhauling the class ability trees.

I, too, noticed the sub-class tendency with the Support class and cranked that dial up to 11 with every class, ensuring that each side of the skill tree had synergies with as much other stuff on that side as possible, while slotting the skills that would be useful to either subclass into the mandatory slots.

For example, on the Support, my skill tree is as follows:

Opportunist (mandatory)
Field Medic / Smoke Grenade
Revive / Smoke and Mirrors
Savior / Dense Smoke
Covering Fire / Grenadier
Deep Pockets (mandatory)
Sentinel / Rapid Fire

With this arrangement, you have skill paths that make the next choice obvious, and only two points where your skill path offers a real decision: Medic vs Smoke, and better Overwatch vs more grenades & Rapid Fire. The only setup that doesn't synergize without a hitch is Medic + Grenades, since those skill sets fight for inventory space, but it's still a stronger character than any vanilla Support and only having three grenades instead of six isn't exactly starving for explosions, and you've got Rapid Fire besides.

So you end up with four viable builds; twice what the default Support has (and the other classes really only have one or *maybe* two decent builds). If you go Medic, you ignore Smoke completely. If you go Smoke, you ignore Medic completely. The original design forced you to take two Smoke skills whether you wanted to or not, and your damage potential was garbage because even with some great Overwatch skills, you needed Opportunist for them to work very well.

Opportunist is a great skill; it's required for the Overwatch side of the skill tree and it's the best of those skills that the Smoke side could get, so it goes into a mandatory spot. Deep Pockets stacks with Grenadier, giving three grenades per slot, and also stacks with Field Medic to give four medipack uses, so that's another mandatory skill. They aren't class defining, per se, but when you're making very distinct skill branches within the same skill tree, "defining" the class gets harder to do and including skills that help both branches takes priority.

In the end, the Support class is far more powerful, and feels a lot less like an obligatory pick that just only take because nobody else can heal worth anything. Every level gives you something cool that makes your soldier better at whatever its job is in a significant way, and there are no instances where an awesome skill is paired with a useless one. Combine it with mods that increase the number of aliens you face or otherwise adjust the difficulty upward, and you're all set.

If you're interested, I can share the other skill trees I've made. I've been tinkering with these things through a dozen different iterations, and I've found that you can get a lot more variety in viable builds by making little packages of useful skills and distributing those across classes instead of giving everyone a mix of useful and useless unique skills.

taw said...

Pax Empyrean: Last time I played XCOM (without Long War) was with training roulette, which "sort of" fixes the skill tree problem of only having a few viable builds, but it has other problems, like making it too hard to get good medics.

Are there any mods that do modest amount of rebalancing and extra content without going all the way to Long War? (which mostly takes too long to finish).

Pax Empyrean said...

Part 1:

Sorry about the ridiculous length of this response; I'm going to break it up into a few parts so it'll actually let me post it.

I'm not sure about other mods, since I tend to just make my own for the fundamental stuff and then pick up smaller mods for specific features. The easiest way to rebalance things is to just do it yourself by editing the DefaultGameCore.ini file in your \XEW\XComGame\Config folder. All you need is a text editor, and when they released Enemy Within they moved a bunch of stuff into that .ini that previously required hex editing to mess with, such as the skill trees for each class. If you want to mess with Training Roulette, it also has a section for which skills are considered options, although I haven't messed with that at all as I prefer my own custom classes over randomization.

That said, the changes I've made might be something you'd like, although I haven't released them publicly and all I could really do is just pastebin a copy of my DefaultGameCore.ini file for you to copy over your own.

Here are a few of the changes in my game:

> Adjusted range calculations. Close range shots are more accurate in general, and range bonuses drop off over a longer distance so there is a difference between firing at medium range and long range. In the original game, anything farther away than about seven tiles had the same chance to hit with anything that wasn't a shotgun. Range matters more now.

> Made assault rifles and shotguns available to all classes. This is particularly important for the Sniper, since one side of the tree makes for a powerful close range ambush character that rewards sneaky play.

> Rebalanced all weapons. Each tier has its own advantages and is viable throughout the game. Different builds will tend to perform better with different weapons. Assault Rifles do 6 damage and have +20 to hit. Laser Rifles 6 damage and always crit (even against hardened targets). Plasma Rifles do 8 damage and never require reloading. Shotguns do +2 more damage than rifles of comparable tier and have the same weapon type advantages. LMGs do the same damage as rifles of their same tier, have -10 to hit, never require reloading, and have the Suppression ability automatically (Heavy Plasma has +1 damage instead, since all plasma weapons are no-reload). This makes suppressing fire a much bigger part of gameplay. Pistols have been boosted substantially, such that for a character with Gunslinger they are about as good as a primary weapon. The default pistol and the plasma pistol have accuracy characteristics like shotguns; very accurate at close range, less accurate at long range. Arc-Throwers take up the Pistol slot, although they still benefit from Deep Pockets.

> Items have larger effects. SCOPES give +20 to hit, HP boosting items give +5 to HP.

> Soldiers have more HP (start at 8, max at 15), but the only armors that give HP bonuses are Carapace and Titan armor (which give +5). While the soldiers aren't any more durable in the end, this makes the HP regen effect from the gene mod a lot more competitive (regen up to 15 HP will actually let you take another hit), and also encourages you to have a deeper roster since any hit will wound a soldier.

> Normalized Will growth across all classes. Removed Will growth variability, incorporated Iron Will into base growth rate so your first characters aren't crap late-game. All characters progress from 65-100 Will depending on rank. All characters have Psi gift; recommend playing with Mind Hates Matter option enabled.

> Normalized Aim growth across all non-Sniper classes. Starts at 60, increases to 80. Snipers grow to Aim of 90. Most characters with a SCOPE will be roughly equal to their vanilla counterparts with a SCOPE. SCOPE plus ballistic weapons makes for accuracy about on par with vanilla Snipers. Heavies are no longer incapable of hitting the broad side of a barn from six feet away.

Pax Empyrean said...

Part 2:

> Rebalanced strategic layer. Continent bonuses reworked and country funding values adjusted to make for more viable options (funding is roughly proportionate to the square root of each country's actual GDP, which actually gave pretty good values). Air and Space and Expert Knowledge both boosted to 75% reduction in costs instead of 50%, with base maintenance costs increased to make this bonus more meaningful.

> Reworked all class skill trees. There are now much more distinct subclasses within each class, although most can mix and match at least a few ways, so there are 3-4 viable builds per class instead of maybe two.

> Sniper class skills:

Low Profile (mandatory)
Close and Personal / Squad Sight
Bring 'em On / Executioner
Battle Scanner / Disabling Shot
Gunslinger / Damn Good Ground
Opportunist (mandatory)
Rapid Fire / In the Zone

The right side of the tree is the standard long range sniper. Don't worry about the lack of Snap Shot; I removed that restriction on sniper rifles. The left side is basically a ninja, with big payoffs for getting up close and flanking an enemy, but none of the Assault's tools for doing this in the open (Lightning Reflexes, Run and Gun). Also makes for a really, really good Special Operations agent. You can mix skills a bit and get a sniper that is really good at mid-range flanking with a sniper rifle, using In the Zone to get back into cover after killing exposed enemies. Recommend playing with Absolutely Critical enabled, so every flank attack is a crit. This character was built around that assumption.

> Assault class skills:

Lightning Reflexes (mandatory)
Run & Gun / Field Medic
Gunslinger / Deep Pockets
Opportunist / Resilience
Rapid Reaction / Will to Survive
Rapid Fire (mandatory)
Close Combat Spec / Low Profile

The left side is a really versatile fighter. The pistol does a base damage of 4 and can be upgraded to 100% crit chance, with +2 from Gunslinger and another +1 from Pistol III it ends up reliably doing 8-9 damage per shot with crits, allowing you to take a rifle for longer ranged work. You can still murder stuff up close like you'd expect from an Assault, and properly leveled you're effectively immune to Chrysallids (at that range, you're doing no less than 8 damage on approach, 100% hit rate, pistols never reload, etc).

The right side is a decent Medic (4 Medikit uses, but only 60% as much healing as a dedicated Medic Support) and distinguishes itself by being ridiculously hard to kill. This guy is great for capturing enemies thanks to Lightning Reflexes, an extra shot from the Arc-Thrower due to Deep Pockets, and all around durability. Especially good against EXALT Elites, whose laser weapons auto-crit for about 9 damage normally. They hit him for 4 damage instead. The first two skills from either branch pair well with the next two skills from either branch, so you can make a tanky close combat guy, or a weaker medic with weaker overwatch but much better single target damage.

Pax Empyrean said...

Part 3:

Heavy class skills:

Fire Rocket (mandatory)
Opportunist / Rocketeer
Covering Fire / Shredder Rocket
Sentinel / Bullet Swarm
Deep Pockets / Flush
HEAT (mandatory)
Grenadier / Danger Zone

Left side is for grenades and overwatch. Works best with an assault rifle or shotgun. Right side is for rockets and LMGs or plasma weapons (Flush costs a stupid amount of ammo, and those weapons negate that). If you really, *really* want to blow stuff up, you can take all the grenade skills and all the rocket skills, ending up with 3 rockets and 6 grenades per battle.

MEC class skills:

Adv. Fire Control (mandatory)
Collateral Damage / Sprinter
One For All / Lightning Reflexes
Expanded Storage / Tactical Sense
Overdrive / Close and Personal
Jetboot Module (mandatory)
Reactive Targeting / Close Combat Spec

MEC weaponry is very good. The Chaingun does 8 damage, does not need reloads, and has +20 to hit, making a left side MEC a very reliable damage source, and you can blow up cover whenever. Railgun does 8 damage and always crits; better against robotic enemies. Particle Beam does 11 damage; worse against robots, better if you can flank enemies. There is no Vital Point Targeting; the +2 damage was just too much better than anything else, so I'd always take it. Figured I'd just remove the skill and add the bonus naturally.

MECs got a few other substantial bonuses to keep them useful, too. An inherent defense bonus of 20, 30, or 40 depending on tier, and a Will bonus of 20, 40, or 50. While other characters deal with psionics via gene mods or their own Psi powers like Psi Inspiration, the MEC just tanks through it with sheer Will. A fully upgraded MEC Colonel will have 30 hit points, same as a max-HP Assault in my game or in vanilla.

Left side is long range fire support, good for Sniper and Support based MECs. Shoot twice if you don't move, and get a free return shot against the first to shoot at you. MEC accuracy advances the same as normal soldiers of the same rank, and the Sniper's +10 Aim advantage comes at Corporal rank, so you don't need to fidget with ranks before switching over.

The right side is based around mobility and close combat, good for Heavy and Assault based MEC troopers. I boosted the speed of MECs by 3 anyway, and with Sprinter on top of that this MEC is stupidly fast. It plays a lot like a traditional Assault, except with electro-pulsing and robot punching. Whereas the left side shoots twice if you don't move, the right side shoots twice if you move within 4 spaces of an enemy. The left side shoots back automatically at the first enemy that shoots at you, while the right side shoots automatically at any enemy that moves within 4 spaces. MECs are the only class that doesn't mix branches well, mostly because the class bonuses tend to push hard for either close range combat or hanging out back with the rest of your troops.

All of these classes are much stronger than their vanilla counterparts, so I play with a few other mini-mods installed to keep the challenge up. One of them is randomized pods, so aliens can spawn anywhere (helps loads with replayability), and the other is increased pod sizes, so after a little while alien pods have one or two extra aliens in them. Cyberdisks, Muton Berserkers, and Sectopods always come in pairs. Alien damage and health has been boosted around the early game, so your guys are still very much vulnerable to getting one-shot even with the extra base HP.

If this stuff looks good to you, I can show you my DefaultGameCore.ini edits so you can try it for yourself.

taw said...

pastebin is a highly respectable mod hosting website, I use it this way myself.

My experience with training roulette tells me that low profile is completely wasted on squad sight snipers, but it's one of best abilities assault can have. Especially Mimetic Skin assault. Especially on large UFOs and enemy bases where there's zero full cover, mimetic skin low profile assault is god tier.

Pax Empyrean said...

If your sniper is always firing from Squad Sight, then it doesn't do much, but with In the Zone, guaranteed criticals on flanking shots, and no restriction (or penalty) on firing after moving, there are good incentives to bring him closer to the action. Muton Elites that have had their cover blown up with a grenade, for example, will survive a squadsight sniper shot every time, but if you're within visual range they'll never survive a hit (and thus you can wipe out a whole pod in one turn if they're all bunched up around destructible cover).

I've got a few tweaks to make to my file and then pastebin it for you tomorrow morning.

Pax Empyrean said...

Okay, so I had a bunch of stuff come up. I'll have it up as soon as I can. Need to change a few things I had been tinkering with back to their original settings first.

Pax Empyrean said...

Sorry this took forever. Still not completely done, but my modding is in a perpetually unfinished state. Couple ability changes, made it so all assault rifles can suppress (at -30, which is what you'd get in vanilla instead of the improved -50 for LMGs), stuff like that.

Flamethrowers seem to be broken, although I'm not sure if it's my changes (which did nothing with flamethrowers specifically) or because of the mods I've got. If you could let me know, I'd appreciate it.

Alien stats are the same in the two highest settings, but the strategic game is harder on the highest setting and there should be more aliens.

I've made big changes to grenades. Frags are longer range, larger blast radius. Needle grenades and Flash grenades radii are gigantic. Alien grenades are a bit shorter ranged.

One last thing; to get a DefaultGameCore.ini edit to work, you need to change a hex value or two to disable the hash check, if you haven't done that already. Instructions here:

taw said...

That's the thing with modding, it never finishes :)
Some interesting ideas you have there.

Pax Empyrean said...

Yeah. I've made a few changes even since I posted the first time here. Swapped out the Assault's Rapid Reactions for Covering Fire; it serves a little better at keeping the point man alive. I also swapped the Support's Grenadier for Flush. You still get two grenades per slot thanks to Deep Pockets, but I wanted a little smoother transition between the Medic side on the left and the stuff on the right toward the bottom of the tree if you go that route. Flush is actually pretty good if you've got squad build that can take good advantage of it; the wider availability of Opportunist, and Assaults and MECs with Close Combat Specialist, makes Flush potentially one of the most damaging options available. Flushing a Mechtoid that's in range of an overwatch-specced Heavy with a laser shotgun can guarantee a kill when it tries to shoot (one shot from movement, another from Covering Fire when it attacks next turn).

My current squad loadout:

MEC, promoted from Heavy (right side, CQB)
Advanced Fire Control
Lightning Reflexes
Tactical Sense
Close and Personal
Jetboot Module
Close Combat Spec

Heavy (left side, overwatch/grenadier)
Fire Rocket
Covering Fire
Deep Pockets

Support (right side, smoke/shooting)
Smoke Grenade
Smoke and Mirrors
Dense Smoke
Deep Pockets
Rapid Fire

Assault (left side, except Field Medic instead of Run & Gun)
Lightning Reflexes
Field Medic
Covering Fire
Rapid Fire
Close Combat Spec

Sniper #1 (right side, except Rapid Fire instead of In the Zone)
Low Profile
Squad Sight
Disabling Shot
Damn Good Ground
Rapid Fire

Sniper #2 (weird mix of both sides, uses a sniper rifle within normal visual range)
Low Profile
Close and Personal
Bring 'em On
Disabling Shot
In the Zone

Normally I'd take In the Zone on my squadsight sniper, but with a close range sniper for flanking/skirmishing it's better to put it on that one. Guaranteed crits from flanking, Close and Personal, and Bring 'em On means you can drop a lot of enemies on ambush. Mimetic Skin is a high priority with this character, and I use them as a spotter for the squadsight sniper.

Oh, yeah... I removed the close range penalty from sniper rifles. They don't get bonuses for any range, so they're still the worst option for up close fighting unless you're built for it. (Assault Rifles go from +0 at 21+ range to +40 at point blank, while Shotguns go from -20 at maximum range to +80 at point blank)

Another fun thing is using Flush and either the MEC or Assault to skirmish with. Move the Assault close and flank the enemy, Flush with a Heavy or Support, triggering the Close Combat Specialist reaction shot, auto-critting if you're flanking. It'll kill a Muton Elite, and then you can move the Assault back into cover. A right-side MEC can do this just as well, being a LOT faster and getting a free shot with Close and Personal, although the Close Combat Specialist shot doesn't crit with MECs.

In vanilla you couldn't do any of this stuff, since MECs had no skills to pull it off, and Flush was on the Assault, so nobody would ever be able to do this unless they skipped Rapid Fire and had multiple Assaults dedicated to it, and Opportunist wasn't available to them.

Field Medic on an Assault is handy, since it gives you an intermediate option between shitloads of healing (dedicated Support) and no healing at all. Just gotta play a little more conservatively with the Assault, but losing Run & Gun keeps you out of the trouble that Assaults usually get into anyway.

taw said...

Is there any way to mod Run & Gun to work with items like medkids? That would be interesting build.

Pax Empyrean said...

You can mod just about anything if you've got the programming chops to do it. I don't, so I'm forced to work within more limited constraints and use other people's mods to make changes that I couldn't do myself.

For example, I downloaded a mod that makes it so that alien abduction missions keep happening even in countries with satellites. To keep from getting overwhelmed, I made changes to satellites so that they always reduce panic by 1 at the end of each month (assuming the country doesn't leave the council). If you play fairly well, once you have satellites up all over the place you shouldn't lose any countries, but you'll still have to bail certain countries out sometimes instead of just picking whichever reward you want the most.

Before I did that, I tried making it so that the alien abductors could be shot down on their way in (like in the original X-COM), but so many extra alien ships per month made the game take forever and cut out the "juggling to keep everybody happy" strategic aspect, and I like having that in the game.

Anonymous said...

Very late to the party, but the other sniper is good if you want to make a dedicated agent for the exalt missions. Also, it's an interesting build if you want to raise one quickly to convert to a MEC.

taw said...

Anonymous: I thought there's a consensus that Assaults are way better as agents as they can run&gun to double move and activate relays.

(for that matter this post was before expansion)