Breaking down XCOM's Tactical Combat

I have a long relationship with the Firaxis XCOM reboots. One of my very early efforts with Unity involved cloning a simplified set of XCOM's core game mechanics. To my surprise, my copy of the strategy layer felt incredibly poor. This was one of my first, very harsh, lessons in 'narrative'. XCOM's strategy layer is intimately tied to the games loose narrative.

The choices you make as you assume the role of 'Commander' are deeply soaked narrative, even if there's very little traditional 'plot' - the game mechanics and the 'role' you assume work together in tandem to create a rich experience. The whole of the result is greater than the sum of its parts: the mark of a superb game.

That said, let's break down some of XCOM's core game play.

TACTICAL COMBAT
More than any other game I've ever played, XCOM taught me that there's simply a massive gap between good strategy for a game, and the player's fantasy of what the strategy is.

• On it's surface, XCOM is a game about tactics, daring flanking maneuvers and tense firefights.
• In truth, XCOM's actual strategy has very little to do with this. The most important element in XCOM is not moving, and the core to a winning strategy revolves around uncovering the fewest possible squares.

XCOM's tactical maps: Enemy 'Pods'
A map in XCOM has a bunch of walls, objects and assorted stuff for your guys to take cover behind. The enemy deployment is built around 'pods' - these are usually groupings of 3 alien bad guys. These pods are scattered randomly around the map.



This image is a breakdown of one of the XCOM:EU maps, and where some of the enemy pods might be deployed. Your men need to move through the area, and clean out each of the bad guy pods.

The Core Strategic Element: Pods won't actively engage you
There are corner cases and rare exceptions, but in the vast majority of cases enemy pods are immobile and will not actively engage the player.

Instead, once the player moves into line of sight, the pod becomes 'active', the aliens in the pod take cover, and at the end of the player's turn they start shooting.

As a player, activating an enemy pod at the end of your turn is the absolute, hands down, worst thing you can do. The result will often be that the game will kill one or more of your little men for making this mistake.

The Core Strategic Tool: Flanking
The game presents the player with one major combat bonus: when you 'flank' an enemy (move a guy perpendicular to, or behind an enemy's cover), you get large bonuses. Flanking is presented to the player as their main goal in any combat situation.

This is emphasized by giving 'flanking' its own color in the largely 3 color HUD.

The color 'yellow' is largely reserved for to either indicate flanking or just a couple special moves. This would not be so meaningful, except the color scheme is largely limited to teal (general info on friendlies), red (bad guys) and yellow (flanked guys).

A huge part of the combat system revolves around flanking the enemy.

Where things get interesting: Punishing the player for flanking

So we have the two core elements to XCOM's tactical design:

• The worst thing the player can do is move into a new square (you might activate a new enemy pod)
• The near term goal for the player seemingly involves moving behind the enemy, this almost always involves moving into new squares.

I do not believe that any other game will punish the player with anything like the severity that XCOM does (potentially one shot perma death) for trying to achieve game's major micro goals.

It's a fascinating design. XCOM's design, literally goads you into flanking the enemy, then kills you for it.

Almost every recent turn based game have copied the shallow elements of XCOM's tactical design. Everything from cover icons, to the movement system, but none have really taken this conflicting player incentive.

There are more really interesting parts to XCOM, and it's design in the large and small - but this core element is so philosophically different from most games, in an era where so much game design revolves around gratifying the player, rewarding him for tiny step forward, XCOM stands in harsh contrast by doing the exact opposite.

 

Interesting stuff. I knew a lot of this on a base level from playing it, but had never broken it down like this. I found this part the most interesting:

I think what you said is true for the most part (although a good portion of the missions also put you under some time pressure to encourage you to go as fast as you can without losing people).It sounds like pretty poor game design to encourage the player to crawl through the game very slowly, but it doesn't feel that bad when you actually play it. I can't help but wonder if the game would be more fun if the pods did actively engage you. It would certainly be more realistic since super advanced aliens would obviously have a way to communicate with their allies that are 100 feet away.

 

I pretty quickly recognized XEU's AI didn't "activate" until you exposed it and personally I found it highly susceptible to run-of-the-mill kiting tactics. Combined with the very limited number of maps and the small size of the maps, I feel they severely crippled something that had much greater potential.

That aspect of XCOM actually bugged me a lot. I'm beta-testing a game right now (Depth of Extinction) that largely clones the XCOM tactical combat system (they hate it when people say that, but I see it as a good thing -- the general system is a lot of fun to me). Their first public release had similar pacing and at the time I didn't quite realize how much the plodding nature of XCOM had bothered me. They've made a lot of subtle changes recently (not only revising the mechanics but also good UI choices) that significantly increase the tempo and I'm enjoying the new flow quite a lot.

 

I might have to check that game out. XCOMs tactical combat is one of my favorite things in gaming. If anything, using that system is a selling point.

 

https://hofstudios.itch.io/doe-story

 

You probably didn't notice the plodding pace of XCOM so much until you were playing an inferior version, one where not all of the elements that went into XCOM are present. This is what I also found with my attempts to clone parts of the game. The bits and pieces I cloned really sucked.

In really, really well made games, the whole is much greater than the sum of it's parts. Different pieces and elements click together. In less well made games, the weaknesses and problems are more apparent.

I don't think the goal of XCOM's combat was to be 'fun' - at least not in the way that we tend to talk about fun (generally ego gratification). I think their goals for the combat were:

• Tons of Tension
• Unknown and Uncertainty
• Harsh Consequences

I think the most important thing here isn't 'fun' - I think the most important thing is 'fair'.

The most interesting thing about XCOM's system is that it so directly punishes specific actions. The connection between a given click and a disastrous outcome is super clear.

"Oh god, I shouldn't have run up to shotgun that alien in the face... now my whole squad is gonna get killed!"

By making the connection between action and consequence so clear, the player is more likely to walk away feeling like they were in control. "I messed up, but I can do better next time" - is far more likely if the consequences are direct. When the consequences are more subtle or disconnected, you're more likely to get "I PLAYED PERFECTLY, THIS GAME IS RIGGED, F THIS".

I think "I can do better next time" is probably the most important ingredient for true replayability. (Maybe it comes second to "I wonder what would have happened if I did ... instead".)

Having the game's main cause of failure be in direct opposition with the near term goal that the game presents to you (flank for a bonus!) - this cannot have been a design goal up front. It's just too weird of a design.

It had to be the result of iteration. The thing that's interesting is that this is where they stopped iterating. So even if it wasn't a fully conscious design goal, they recognized that that conflict created the game play they wanted.

 

I don't agree that the "worst" thing you can do is activate enemies at the end of a turn. The worst thing you can do is run straight through the level like a lunatic and activate enemies while you're standing in the middle of an open area. But if you move from cover to cover, it's not a problem at all. If an enemy "pod" appears at the end of your turn, with you in cover, then they'll spend their first turn either taking shots from too far away or maneuvering closer to you.

Nor can I agree that the game "punishes" you for flanking. The game punishes you for running out in the open. It punishes you for charging straight at a group of enemies. But I would frequently discover a "pod" (in the more natural environments like your picture above you kind of learned where to expect them to be) then slowly creep up on them until I got to a flanking or otherwise sufficiently lethal location where I could take them out freely.

As for other games which work in a similar manner--Wasteland 2, the Shadowrun games by Harebrained Schemes, and I imagine most ranged combat "tactical RPGs." Probably Jagged Alliance 2, though I couldn't make it 10 minutes into that game.

 

In the early missions (where the difficulty level is by far highest in the game) a single shot at a dude in high cover will kill him about 1 in 15 times. So you should lose a guy pretty reliably about 20% of the time on the next turn per 3 active enemy. If they can flank you on the turn you activate then chances are probably closer to about 50-60% of losing a dude outright.

The odds and stuff change depending on how far into the game you are, the difficulty level, the exact pod, etc. This roughly around like gatecrasher (mission one) on commander.

The difficulty curve in XCOM 2 is also really interesting - EU had a similar curve - but in 2 I think they were much more specific about the story and difficulty. I think, in general, the hardest mission in the game is gatecrasher (the first mission) on commander or legendary. Every now an then you'll generate an exceptionally hard map, but it's really rare, the proc gen is shockingly consistent (they must have done an insane amount of work here).

The difficulty overall also tends to peak as the story begins in full then drops off rapidly. So, the first real story mission (give or take) is the 'make or break' point in the game.

So XCOM 2 difficulty is organized like this (roughly - at commander, legendary is slower and I never beat legendary ironman, so i'm not sure about the end game):
Hour 0: VERY HIGH
Hour 5: Low/Medium
Hour 10: HIGH (first story mission)
Hour 15-20+: Low (story missions come fast and furious here, and you roll through the rest of the game)

They very intentionally timed the difficulty to drop to near zero once the story missions start in full. I am fairly certain that the most frequent point people give up a failed game is either at mission 1 or right around the first story mission.

They front load the difficulty, cuz like, people would get really mad if you wiped their team on the last mission 30+ hours into a game. Most of the mid-late game upgrades are so absurdly broken that it's almost impossible to lose a guy. This design is like 100% intentional.

Note: Wasteland 2, Shadowrun all use very very different and more conventional level/encounter design. In JA enemies are all active at all times, XCOM will specifically deactivate AI so you don't get overwhelmed unless you activate them via movement (remember, fairness).

 

It's been a while since I played XCOM (I didn't play the second one), so I may have been conflating some stuff with Wasteland 2, which I've played more recently.

 

I put a ton of hours into EU/EW/2. I also tried to copy a bunch of stuff (and failed!), so I'm pretty confident in my analysis (probably a small mistake here and there).

Trying to clone bits and pieces and failing though, that was a weird experience. What seems simple on the surface - it really isn't - there's a crazy amount of work that went into making those game mechanics click together. It's nowhere near as easy to copy as it seems, many games did a better job copying stuff than I did, but it's not a coincidence that none of them deliver the same level of experience that XCOM does (imo).

Again:

I think both these comments are really telling, and show what good a job Firaxis did.

 

Are the XCOM 2 maps procedurally generated? Not the same handful over and over like the earlier ones? Maybe I need to pick that one up after all...

 

Yeah - they did a kick ass job on the random generation. They have mod tools to extend out the map generation, so info on how exactly they organized it is public and it's modular enough that modders can add stuff (I think it's like a hrybrid half tile approach). I haven't really looked at it in detail, but the results are top notch. The maps feel about as hand crafted as they did in EU/EW but each map feels surprisingly unique.

If I were doing proc gen, I would really dig into the modding tools and take a look at how they did it. Whatever it was, it worked. Probably one of the best, if not the best procedurally generated map systems I ever saw. Miles ahead of diablo - which felt super repetitive.

 

Didn't xcom 2 mostly solve the "crawling forward" problem by a) starting you off in stealth mode on most missions where you can see the tiles that will activate the enemy AI, and you can get quickly into positions to lay an ambush, and by b) having timers that force you to move towards the objectives on most missions?

 

Bumping a semi-old thread, but XCOM 2 is on sale on Steam right now, 60% off.

 

@frosted: about the RNG to hit chances we talked about in another thread: I've started a second playthrough on commander difficulty and I'm pretty sure the RNG is biased in favor of the player in the easy mode. I don't remember raging much at things like missing three 70%+ shots in a row on my first playthrough, and now I'm basically ragequitting even when I'm still winning the fight, because I find the amount of missed shots so aggravating. I'm still very sure I would enjoy the game more if there was a way to get the to hit chances to 100%, like in JA2 where you have more fine grained control on how much AP you want to spend aiming your shots.
Maybe the idea of "xcom chess" should really be tried some day. Imagine equipment and abilities give your characters different kinds of chess moves to perform, the base class dictates the kind of move they always can perform, and the enemies are locked in to 1 move pattern per enemy type, no healthpoint system needed, all attacks kill instantly.

 

It's only fun if you don't play against a Wookie.

 

Wait until you play on legend and the dice are fair

It's pretty amazing how hard the game cheats in your favor, and how little we actually notice! If you have any RNG at all in a single player game, you gotta cheat in favor of the player.

The really amazing thing is that if you go on the XCOM forum, people will insist the game is cheating against them when it's still actually cheating in their favor!

I also kinda wondered if we just misunderstand % chance and maybe ratios might make us assess the chances better. Like 70% is close to 2 out of 3 - so 1 in 3 times it wont work. I wonder if we show chance in ratio if people would be less likely to rage

 

My gut feeling is that the general public would be even worse at interpreting a ratio. And you still have to think about presentation. I bet that stating 1-in-3 to miss would produce a completely different reaction than 2-in-3 to hit.

I bet there's a tipping-point where that's true of percentages too. For example, telling them 40% to miss might make a miss easier to swallow than getting their hopes up by telling them 60% to hit. UX sleight of hand, more or less (no pun intended)...

 

This is super true. I actually tested it! I presented chance to miss instead of chance to hit. It really transformed how you thought about the odds. Only problem is it felt too weird, we've all played waaaay too many games that use "chance to hit" - reversing it is too weird and felt bad :'(

 

I think the opposite is the case. I already convert those into ratios in my head, and that's exactly what leads to expectations like "2 out of 3 shots should statistically hit on a 70% shot, I've already missed once, the next one should be a hit". When that one misses again I start to get angry and think "ok, the next one must be a hit now", and when that one misses again, I might ragequit in a game that I can just save and contine later. Imho true randomness (like the chance of missing three 90% chance rolls in a row) for to-hit chances is inherently un-fun and the numbers should be fudged in a way to make deductive reasoning about results work to a degree. Like pregenerate 1..100 and sort the numbers so that every 10 numbers you've gotten one of the possible 1x, 2x, 3x,..9x results at least once, and make sure that no sub-50% results come more than twice in a row. I think that would be a lot less frustrating to play with, because it eliminates the extreme bad luck in a row situations.

 

You may want to check out a game called "Hard West" http://store.steampowered.com/app/307670/

They had a really interesting twist, where your guys have a 'lucky' stat that changes depending on hits and misses. It may actually be close to the way that xcom fudges the numbers for you, only they straight up made it into a game mechanic.

It sounds like this may be right up your alley (still allowing for some chance, but having it be much more under control). I loved it at first, but found that after a while, it took a lot of the tension and excitement out of the game for me. We all have different taste.

 

It's frustrating as hell, I had three 95% misses while playing Torment yesterday (and those are even more painful than most games, since you improve your chances by spending skill-points from a very limited pool). Even so, I'm not personally a fan of fudging the numbers -- or rather, if they're fudged, I don't think there is any point in expressing your chances as a percentage. Probably I just have a pet peeve about perpetuating wrong thinking.

To be clear, I absolutely agree it's the game's job to fudge the numbers in the name of enjoyment over mathematical correctness, but why not present it as a less-specific graphic, for example? Fill the bar, improve your chances.

I like that: it's not a hack, it's a feature!

 

As a guy who fancies tossing dice in real life now and then. It's amazing how cruel truly random chance can be.

The human brain is completely unequipped to properly handle chance. We can't grasp it: "I'm pretty sure that if I wear my red shirt and green socks, then the dice are more likely to roll sixes At least that's how it works on odd days when the third moon of Jupiter is visible".

 

XCOM has a system (though you may be able to turn it off) that stores the RNG "seed" before combat (before each round, anyway--I don't remember exactly). That means if you reload and try the same action, it will have the same result. This can be exploited.

The way I found to play XCOM was to, at the start of a turn, define my action for each squad member. Then go through them, one by one, and find the character that was "successful," reloading as necessary. If 2 characters missed, one character hit, and the next character got a crit, I would make that last character my first "move." Then just move through each character like that, until all of them have been successful.

It makes XCOM more of a puzzle game and less of a poor tactical game.

 

I think the cautious play style was fairly criticized as a weak point for EU, although I actually liked this type of gameplay, as it emphasizes the tension and suspense, as was mentioned. Typical cautious play was to set everyone up for overwatch, and have one soldier move a few tiles to test out pod triggers. I despised the timed maps and terror missions, which forces you to go out across the map rescuing civilians, putting your soldiers in harm's way of the melee type cryssalids. But regardless, it gave the game variety and forced a different play style.

I never finished EW, as the timed container "rewards" didn't feel too much as an integral part of gameplay, and it was a blatant attempt at fixing the overwatch turtling issues.

Currently in the middle of XCOM2, which I'm enjoying quite a lot.

Spoiler

My next task is to skulljack a Codex, which sounds pretty damn difficult.

I was hesitant about the Ranger's melee attacks at first, but over time, I've felt more comfortable with it, as long as you have a covering unit, in case the Ranger either misses or fails to completely take out the enemy. The new items and abilities are great, and not "just there to add content". Some new valuable additions are flashbangs, mimic beacons, and the much improved Specialist class, over the Support class. I love sending my drones out to hack a mech, or heal a team member at distance.

Overall, XCOM2 tactical is far better than in EU, but where it falls weak is in the Strategy game with its overwhelming tasks on the world map. EU may have been sparse with this sort of thing, but it's like XCOM2 went overboard with it.

Apologies for going beyond the tactical analysis, but I hardly ever play any games, and the new XCOM franchise makes me feel like a kid again (I never played the original X-COMs, as they seemed pretty dry to me). Like, I wouldn't mind if there wasn't another sequel, as the Long War mods can keep me busy a long time, and if I ever go through that, there's always the mod tools.

 

This is so funny: I´ve been making my own XCOM combat clone in unity, seeing that all the 'admin' stuff in XCOM was a drag, and finding that having only the core mechanics is 1) quite hard to nail, and 2) not so fun... Great to see others having the same experience. I love XCOM and XCOM2 though. Would be cool to see some of your demos, to compare...

 

This post highlights EXACTLY everything I hated about the reboot.

The original was SO much better...

 

I'd love to read about your take on how it's better. I mean, I've read a few reasons, like the tension was far greater, more gear, your base gets raided, multiple bases, etc. But what turned me off was the UI, even something as simple as having a "kneel/stand" option. It didn't make sense to me to "command" your soldiers to kneel. I can easily imagine commanding soldiers to go to specific cover positions though.

Have you tried Xenonauts? I'm curious if it captures the same level of "spirit" as the original, or if it really did come off as a cheap knockoff.

I'm looking forward to Phoenix Point, but as usual, I wait for reviews nowadays, because I can't be wasting my precious time.

Also, I've played through a few levels of Mario+Rabbids Kingdom Battle, and while the gameplay may be good, I can't get past the aesthetics, but that's just me.

 

I have, and Incubus, and Jagged Alliance.

They're all okay, but never really captivated me like Xcom.

To start I will say that I do prefer the two actions format, so I'm not completely going all nostalgia goggles here.

BUT, I don't like how the world events unfold exactly the same every game.

I don't like that it is impossible to keep all the countries.

I don't like how all soldiers are basically the same, and how THEY tell YOU what their specialty is rather than you pick it based on their different talents.

I don't like how the game discourages fanning out because at any moment you may stumble onto a pod of aliens, which is a load of crap. The aliens should move about the map and kill people in the shadows. That was WAY more horrifying and tension building than "oops, stepped on the wrong tile by sheer chance and now I'm screwed."

And yes, no invasions. One base. And I liked crouch! Should have added prone.

Xcom 3 should have been more of the same, but in space and their home worlds.

Then release a version where you play 1 and 2 at the same time, that leads into 3.

But now I'm just talking crazy talk.

 

@aer0ace I tried Xenonauts, and it is indeed great for the most part, and I would recommend it. However, from what I can remember, you can't sell corpses (literally how I won the original lol) and it doesn't have the same level of resources / inventory micro-management as the original X-Com, which was an extra level of strategy. They've become dirty words, yet they were one of my favourite things about X-Com in the first place.

Also, Xenonauts is ruined by the air combat imo, because later on it gets too damn hard. I never finished it...

 

I always forget about selling corpses then get a fat stack in the middle of the game when I do remember.