A Few Of My Favourite Artificial Intelligences

I’ve been playing a lot of Civilization 6 recently and I love it dearly. It’s not perfect though. Nothing is, of course, but Civ 6 also suffers because it’s a strategy game so it has all kinds of problems with its AI. When I first started writing a critique of what does and doesn’t work when it comes to the AI, I rather lazily typed out something like that previous sentence: “has there ever been a strategy game with AI that is praiseworthy rather than passable?” There’s a part of me that has become an apologist for clumsy AI routines in strategy games.

Here are a few artificial intelligences that need the fewest apologies.

The fact is, it’s not just strategy games that suffer from bad AI, is it? And maybe “bad” is the wrong word, because if there’s no “good” AI to rate it against, isn’t all AI perfectly fine? What are our expectations of what AI should and shouldn’t be able to do? I often say that the best AI is the one that convinces me I’m playing against a person, making mistakes, reacting to strategies, exhibiting signs that it has a character distinct from other opponents.

To an extent, it’s much easier to be convinced by an AI in a game that has either very simple rules or extremely complex, opaque rules. Civilization falls somewhere in the middle – it’s impossible not to notice when an AI nation churns out loads of settlers and has nowhere to send them. It should realise that it’s wasting resources and stop producing settlers but some trigger has told it that it needs a new city and it’ll just keep going through the motions until a new trigger over-rides that one.

I’m sure there are similar loops in other games but Civ’s transparency – all of the rules and actions are easily knowable – makes it easier to spot the tipping point when the AI starts running straight through the hurdles and ends up lying on the ground full of splinters.

That said, I thought it might be fun to think about my favourite AI in games. Not the SHODANs and other villainous computery sorts, but the AI that drives games.

Crusader Kings II

I’m probably overly forgiving of CK II’s AI because I play the game as an RPG as much as a strategy game. If I tried to figure out how best to manipulate other characters, I might find their fatal flaws all too easily, but as it is, I’m playing to see a simulation of history rather than to win. Whatever the case, if a game can play with itself and create compelling stories, the AI is doing something right. Open up the console (` key by default in the UK) and type ‘observe’, then ‘fow’ to reveal the world. Now you can accelerate and watch history generate itself.


People often talk about Half Life’s soldiers when discussing FPS AI. “The barks,” they’ll tell you, “the barks were the key”. They’re not wrong. The soldiers speak to each other, telegraphing their intentions, and that makes them seem like they’re acting as a team, thinking and communicating. They’re great.

F.E.A.R. wins though, because the soldiers there are absolutely terrified of the player character at times and listening to them panic as they react is preposterously entertaining.

Deadly Premonition (and others)

Alice suggested this, pointing out that it’s more a scripting thing than an AI thing. If you haven’t played Deadly Premonition, know this: you can follow characters as they go about their lives, spying on them in their homes, watching the as they potter about the place. It’s great: both authentically detective-y, and absolutely weird and creepy and sinister.

If the strength of some AI is that it can go off-script, just as an actor can improvise when circumstances demand, the waxworks of Deadly Premonition feel like the residents of a haunted house. They’re on-rails, unable to escape or deviate.

There’s a whole subset of games that have this type of AI. I wrote about my favourites here.

Grand Theft Auto V

Following pedestrians, watching their weird interactions, seeing someone drop a coffee as I brush against them and then seeing the styrofoam cup roll into the gutter. GTA V often bores me when it should excite me, during its heists and high speed chases, but in small moments, its world feels convincingly inhabited.


A turn-based survive ’em up that makes me feel hunted and afraid more effectively than a multiplayer kill ’em up or just about any survival horrorgame. It’s in the combat that the AI really shines, not because it’s good at fighting but because it seems clumsy, terrified and like it’d rather be doing anything else but will absolutely cut you to ribbons with a shard of glass if it has to. After all, you’ve got a nice pair of shoes.

What’s your favourite AI?

Mine, despite all of the above, belongs to these mushrooms that Alice found.


  1. spearhavoc says:

    AI War. Arcen designed an AI that operated by completely different rules than the player, and didn’t pretend otherwise. It hit a sweet spot where it was smart and unpredictable but could still be manipulated by a careful player (had to be, in fact). It was fun to play against, and I wish that more strategy games would get on-board with this type of AI.

    • protorp says:

      It seems appropriate to add that Arcen currently have a Kickstarter running for AI War II. It was mentioned on RPS a week or so back, but not since… and it’s not been drawing in support at a brilliant rate. So if AI War sprung straight into your head when you saw the title of this article, the Kickstarter may be worth a look. Backing aside, there’s a link from there to a 160 page design document for the sequel which gives some pretty interesting insights into the way Arcen go about designing and implementing things. KS is here: link to kickstarter.com

      • SaintAn says:

        It’s been going a week and hasn’t reached its goal yet? Sounds like a winner.

      • brucethemoose says:

        Oh man, $300,000?

        I think the devs set the bar a little high. It’s not going to make it :(

  2. Dorga says:

    Catacob Kids’ grumbuls are neat.

  3. Overload-J says:

    Command Ops 2. It has the exact same tools and information you have (it has less if you have played the scenario before!) and will usually kick your ass through superior planning.

  4. DelrueOfDetroit says:

    There is this one fun little AI quirk in Brigador where sometimes when an enemy is by itself it will retreat and try to join up with another group. What this of course ends up looking like is a person in a tiny tank takes a left only to see a 12 story tall mech and immediately craps their pants.

  5. MOONRGR says:

    At first I thought Alice’s video was just being funny, but the latter part of the video, especially the line “the answer for someone else is not necessarily the answer for you” really gets me to think.

  6. ArbiterLibera says:

    No Galactic Civilizations 2, game where one of the factors that affects enemy AI is how long you took with your own turn? For shame.

  7. Jac says:

    “There’s a whole subset of games that have this type of AI. I wrote about my favourites here”.

    There’s no link on the word “here” btw (seems like there was meant to be?). I wish to click it.

  8. Banyan says:

    I thought the AI Director in Left 4 Dead 2 was surprisingly good. Over many rounds, you could actually see it reacting to how well your team was doing.

    • SlimShanks says:

      I was gonna mention this but you beat me to it. I read that the game tracks stuff like how much each person misses, gets hit, looks around, and it even tracks relationships between players. It knows who is tight with who based on teamplay, item usage, proximity etc. On harder difficulties it will use this info against you to target the best player or the weakest link. Cool.

  9. BluePencil says:

    I played Stellaris the other night. The first competing empire I made contact with I insulted (I was a xenophobe empire) and it quickly went to war with me and took my empire capital. Had this been my first game of Stellaris I would have found this off-putting. But it wasn’t and I actually appreciated that their empire saw it could destroy me and went for it because my empire was anathema to them.

    It left me with a (short) story arc of my brave species venturing off to space with all its hopes and dreams but hitting calamity due to its racism.

    • SaintAn says:

      I went to war with the first Fallen Empire I met which awoke and kicked my federations butt, then befriended the second that awoke and got them into my federation, and literally shattered the third into 5 smaller liberated empires yesterday when it went to war with me because it was xenophobe. Wonderful game with many fun stories.

  10. Smurph says:

    I would argue that EUIV had better actual game play AI than CK2. CK is usually about gobbling up all the smaller counts and dukes around you, and they would rarely do much to stop you other than raise their smaller army and fight one doomed battle. Sometimes they would end up being allies with a powerful king who could stomp you, but that’s rare and easy to avoid.

    EUIV’s AI though was all about survival. It is really good at working to find the right alliances to keep it out of wars it will lose. It was also merciless when it saw an opening, quick to attack you in the awkward years between major alliances or in the aftermath of a big war where you lost lots of troops. I haven’t played the game in a while and I’ve heard it doesn’t handle some of the new features well, but back closer to release it was solid.

    • ThePuzzler says:

      EU4 AI is an interesting case because it’s mostly predictable. Will the AI come to my aid if I go to war? The answer is no – if I hover the mouse over his name on the right screen, I find he has a score of -7 for this decision. Looking at his stats, I see this is because of a number of factors; he likes me because I improved relations with him and dislikes the guy I’m attacking, but his people are war-weary and he’s heavily in debt. So if I give him a lot of money, he’ll probably use it to pay off his loans, and that will push him into the positives.

      This makes AIs easy for a human to manipulate (unless they’ve chosen you as an enemy), but their actions are generally realistic and their decision-making becomes a game mechanic you can interact with.

  11. SlimShanks says:

    Hmm, two games come to mind immediately, both shooters (ugh, men). The AI in Arma 3 is actually ridiculed a lot, but if you take a step back and look at everything it can do it is kind of mind blowing. Then you include AI mods and things get really interesting. I ambushed a squad of AI in the middle of a field and they immediately threw smoke, spread out, and sprinted to the nearest piece of cover 30 metres away. Wow.
    Also Stalker Misery always gets a mention from me. The number of times the AI has surprised me in that game/mod is unreal. I love how people hide behind bits of grass in combat, and how a squad that hears a weird sound will stop, get down on one knee and look around before continuing.
    I’ve also heard that the new Forza AI is really good but I haven’t played anything past number 4 :(

  12. SqueekyMcClean says:

    Alice, could you please make a video series about you giving advice to random NPCs? With this exact kind of soundtrack.

  13. Sin Vega says:

    I’ve thought for a long time that AI is probably the biggest disappointment of games in the last 15 years or so. For all the insane advances in graphics and physics and generation of worlds and resources, it seems like most games have AI that’s barely distinguishable from similar games made over a decade ago.

    I’m sure that it’s not THAT true – there’s a lot more going on behind the scenes that I don’t notice because I’m not a programmer, and there’s probably an element of Red Queen theory going on with the increasing demands of complex simulations. But that I perceive it to be fairly static is still pretty disappointing when you look at how standards of design in most other regards have visibly moved on.

    Anyway. I always liked the AI in the original UFO/XCOM, not so much because it was super advanced, but because it felt, well, alien. For the longest time, the behaviour of aliens and their ships feel so inscrutable and hostile, it really fits the theme. I even read accounts of modders who refused to do anything to the AI because they didn’t want to know how it worked. It was all fairly simple, as you’d expect for the early 90s, but the smoke and mirrors made it work. And enemies in Apocalypse would assume that any small object (e.g. a clip) you threw at them was a grenade, and take cover.

    More tangibly, AI War, obv (Kickstarter for the sequel needs help damn it! link to kickstarter.com). Alpha Centauri had AI rivals that behaved reasonably and in character, to the point where alliances actually meant something and were something they often actively contributed to.

    Far Cry 2 had a problem with foliage being absolutely worthless concealment, but beyond that the AI was really impressive. They moved, the co-ordinated their attacks, they communicated with each other rather than just shouting stupid things designed to help the player. They were too good at spotting you, but unlike most shooters, there wasn’t a binary “no idea you’re here” vs “we can see you no matter what you do now” system, so if you kept moving they’d lose track, and start looking for you based on where they last saw you. It made harassing them great fun. And utterly horrible when, in the course of skulking about a base while everyone panics, you hear the piteous cries of a sentry you winged earlier as he crawls off to die. Brr.

    MGS 5 had great AI too, obv, which made fucking with them fantastic fun. Hardwar’s AI was had some easy exploits (it was totally helpless and braindead in lightwells and tunnels, finstance) but its general behaviour was much more convincing than in most similar games (including its X siblings), not least as pirates were actual pirates who just wanted to make money off your cargo, not mindless omnicidal monsters.

    The Gothic games, for having AI that reacted to suspicious behaviour by degrees, warning you to put away your weapon and coming to challenge you if you were creeping around somewhere private (contrast with Fallout 3, where you’d be constantly accused of theft for literally glancing at things). And less violent characters got scared and backed away if you got aggressive, and even animals gave threat displays and chased you until it was satisfied you weren’t coming back. And most humans beat you up and robbed you instead of murdering you over nothing.

    I liked some of the details in Hitman Blood Money, especially the first time I was casually striding through a building mid-rampage, and one of the helpless cowering tourists picked up a fallen cop’s gun and shot me. Most embarassing Hitman death ever, and it was brilliant. Not long after that I realised I could give isolated witnesses the choice by throwing them a spare gun.

    I dunno, most games with great AI aren’t even particularly complex, but they either offer a convincing illusion or have obviously thought about the player’s experience and what does and doesn’t make sense or emphasise the divide between playing a game and gaming.

  14. anHorse says:

    Alien Isolation

    I’m not sure how much is actually AI but it’s very effective at providing stealth gameplay that’s actually challenging without just being a case of solving a puzzle

    • bbungle says:

      This is what jumped out at me too. Lots of people bounced off Isolation because they found the AI ‘cheaty’, but once you gave it a chance you realise how grounded it is. It’s one of the only games where I felt like I was playing against an actual thing. I was also super impressed that I was still getting surprised by it at the end of the game, considering it’s (essentially) the only main enemy for 15 hours or whatever it is.

  15. Fungaroo says:

    Not sure if it counts as an AI, but Dwarf Fortress’ systems and their interactions can be amazing to watch much of the time. It is interesting, as a previous commenter noted, that it feels like game AI’s haven’t really evolved, because there are AIs that can adapt to real time conditions in other parts society at the moment.

  16. criskywalker says:

    It seems that the current state of A.I. in games is simply pathetic, especially when games like F.E.A.R. seemed to indicate that gaming would really move forward. That game probably used scripting in a smart ways, which probably gave an illusion of an even better A.I. than it really was, but still, that illusion was just fantastic!

    It’s a shame that games nowadays have barely any difference and in some senses even seem to have taken steps backwards regarding A.I. comparing to games released 15 years ago.

    The examples used in this article are really good. I liked the reactions and unexpected behaviour in GTA 5. That’s what we need more. Small details that make the NPC seem more alive.

    I would also like to mention Black & White 2. It really gave the impression that you were teaching your pet. We need more of that!

    After watching Westworld, which feels so much like a game, I want something like that. NPCs with a daily routine which follow a script, but can deviate from that and adapt to what happens around them. An NPC that meets another NPC and then they interact with each other, going around their routines doing their own business. That is much more interesting than all NPCs only reacting to you.

    I wish more games would also take inspiration from Dwarf Fortress and its complexity and unpredictability. We are fine with the graphics we have nowadays. What we really need is better NPC behaviour and A.I.

    • Napalm Sushi says:

      I think the dominance of copyright and the absence of intra-industry cooperation is starting to become a real problem for some of the more technical aspects of gaming. What should be advancements instead become curiosities; nobody’s adding to the work of others and every game is built essentially from the ground up.

      We probably won’t see noticeable universal progress in a hard problem like game A.I. as long as gaming continues to be just an entertainment business.

  17. Swordfishtrombone says:

    What is with Alice’s Shatner impersonation in that video.

    • DuncUK says:

      That’s what bad voice acting sounds like. So yeah, sounds like a Shatner impression.

  18. geldonyetich says:

    The tricky bit with AI is that it the goal is not to make them perfect, because a perfect opponent is unbeatable, or will at least tie with a player that plays perfectly.

    This realization ruined fighting games for me. The whole genre. I realized there is really no reason the AI could not faultlessly block every kick or punch you send its way. Each time you hit an AI opponent in Street Fighter Whatever, it’s because the developers took pity on you and made an AI that chose not to block.

    Extrapolating from there, any AI that works from a competative standpoint as a sarrogate of a player who plays as the same rules you do is inherently terrible. Either the developer was too lazy to make them as good as possible, or they made them deliberately have flaws. Either possibility is inherently bad.

    So the AIs I like the most are AIs that take roles that are not sarrogate players. NPCs. Directors (Rimworld or Left4Dead). Procedural content generators. Ect.

    • geldonyetich says:

      The reason I like AI in NPCs is because they can be flawed foils and that’s fine. Sometimes, a game needs a foil, and NPCs have no problem being that. Games like Left4Dead or Killing Floor would not be possible were it not for the foils.

      The CIV VI AI is that. It is not there to be a sarrogate player. It is there to be a larger-than-life personification of a historical figure the player can beat.

      In other RPS Civ VI entries it is mentioned the unique rules of conduct enforced on the AI make the player, unfettered by those rules, an alien. It is underlined as a flaw.

      It’s not a flaw. It’s working as intended. If you need a player, you get another player. The AIs in CIV VI are NPC foils.

  19. Benkyo says:

    The first one that came to mind is Keldon’s AI for Race for the Galaxy. It plays the game well and I am unable to guarantee a win against it. Obviously chess and go AI is amazing these days… but aside from these examples I honestly can’t think of a single other game that has decent AI.

  20. kud13 says:

    S.T.A.L.K.E.R. ’nuff said.

    • keefybabe says:

      I still mourn the death of stalker 2. I played the death out of the chernobyl series of games. Sod it, I might reinstall them.

  21. solymer89 says:

    I have no favorite AI. My struggle began at a young age while playing Madden NFL football games. I noticed all too often that the computer was perfect in their execution until a trivial point in the game when they would finally make a “mistake”. It really wasn’t a mistake though, it was programmed in. This combined to give me a puerile yet visceral response, and the need to purchase many controllers over my days for I couldn’t accept that a computer was better than me…

    It was apparent that the only way a computer opponent could compete properly was to give them an unfair advantage, and sadly, to this day that remains to be the case mostly, though I have little experience with the titles suggested above.

    This all leaves me to never pay any attention to difficulty levels in games. I’m generally more interested in the mechanics/story in most of these games. For strategy games like Civ I tend to try to push the limits as my familiarity with the game grows and I can easily overcome some of the lower levels. For me, I don’t see any point in playing on Deity as it seems to be an exercise in gaming the system as much as you can, pouring over every decision and that is just not fun to me, because even if I come out victorious, it’s empty and hollow. I take much pleasure in defeating a human opponent though, again to a puerile yet visceral response.

    I’m probably a bit touched in the head though…

    • Grim Rainbow says:

      Yeah, I play at a difficulty in any game where I’m enjoying the experience the most and seems most fitting to the game. I love PvP and competition but I don’t get my kicks from playing against the system’s hardest setting unless that difficulty makes sense for that game. A computer truly let loose is going to kick most people’s ass all over the place anyhow. Playing Civ 1 on Deity isn’t fun more me. Civ is my go to relax game and I don’t want to spend 30 hours being blitzed by Russia. I’d rather pick Prince and spend 30 hours being blitzed by Russia.

      I read recently that they decided to not add alliances in Civ 1 because the AI was too good at manipulating that. I’m not sure what that means, but it was interesting to hear a nugget like that about an old classic.

      Been putting off Alien Isolation due to wanting to play it in VR and because I’ve heard a lot of conflict over what the best difficulty is for that game.

      • Grim Rainbow says:

        I mistook your ‘I’ for 1 with regards to civ. Same point though.

      • Hedgeclipper says:

        Thats a bad example though, Civ’s as doesn’t get any smarter or the computer get ‘let loose’ it just gets more bonuses as the difficulty goes up.

  22. Neutrino says:

    Suprised not to see an Alpha Centauri mention here.

    Also where does Endless Legend fall on the AI spectrum? Only just started playing it myself so I don’t have a view yet but would be intereted to here what others think.

  23. Unsheep says:

    ‘AI War’ would be one of them, dealing with the AI was certainly very challenging in that game.

    They are raising money for a new ‘AI War’ by the way:
    link to kickstarter.com

    Most of the racing sims I’ve played have had really good AI: Milestone’s SBK and MotoGP series, Reiza’s Automobilista and Stock Car Extreme games, Sector3’s RaceRoom content.

    In the RaceRoom stuff they’ve even adjusted the AI to suit the particular Experience/Championship you are doing; for example in DTM the AI is very aggressive, as things are in the real-life DTM.

    The early X-Com games and the Men of War series had some really tough AI.

    The Last of Us and GTA V both had great AI.
    Alien Isolation on harder difficulty made the AI smarter.

    As far as FPS/TPS goes I’d say: the original Rainbow Six, the early Operation Flashpoint and Ghost Recon games.

    Perhaps the AI in FEAR was impressive at the time, but by modern standards it’s quite dumb. What makes them appear smart is that keep stating their actions: ‘taking cover’, ‘flanking’ etc.

  24. Captain Narol says:

    Qvadriga !

    The AI-chariotters are all vicious bastards trying to damage you if they can and you really have to guess what their next moves will be to have a chance to finish the race…

    Also, Mordheim : City of the Damned. The AI warbands are good at finding the weak spots in your own warband and hit on them mercilessly !

    • behrooz says:

      Oh man. Qvadriga. It really was so good, but I was saddened by the limited interplay between the tactical (individual races) and strategic (competitors/equipment/etc)

      If you managed to kill an enemy Auriga, sure, it was cool, but it didn’t affect anything other than the leaderboards, where sometimes you could knock off the current front-runner and take his place.

      Putting special effort into killing the horses and aurigas and damaging the chariots of your competitors had no effect at all outside the race you were in, so it was a negative-sum game where any strategy that did not avoid aggressive contact was a long-term loser, as your repair costs build up and the opposition continues to field chariots with no notice of the fact that half of the chariots, horses, and aurigas in their last race left the field in pieces.

      Now if it had had an economy simulation where putting serious hurt onto the other factions’ entrants affected the starting conditions for future races, that would have been incredible! A hard-fought victory or second-place where you devastated your hated rivals even without winning would be worth something in the game’s ruthless calculus of profit and loss– even if you lost, they lost more, and those rat bastards would think twice before trying to run you off the edge of the hippodrome next time!

      …I want Qvadriga 2, with persistent local faction resources, vendettas, and opportunities for pyrrhic victories.

  25. FOARP says:

    I see some people pushing the line that AI can be made ‘perfect’ but isn’t because it would beat you. This isn’t true for anything but the most formulaic of games, or for games which are entirely based on reaction-speed or following a racing line. The basic fact is AI in strategy/FPS/RTS games is as good as they can make it right now, and that’s still not very good. If you find AI hard beat, it’s normally because the game itself has been weighted in the AI’s favour through giving it extra units/resources/etc.

    The people who point out that AI hasn’t improved as much as you might expect based on processing power are closer to the mark. AI is still being hand-coded and as such is basically a predetermined script that cannot adapt, making exploits inevitable. Once learning algorithms, and more importantly so-called “deep learning”, finally make it into computer game AI, then you’re going to see a real challenge.

  26. BeneSkywalker says:

    The AI “learns” how you play and adapt the tactics to it, if you are used to run back to get cover all the time it saves your behaviour and start to act to address it. Trying different things till find a suitable response to if, like istead run to you the enemy start throw some granades over and over.