AI: Max Payne VS The Last of Us

One of the things that I see little to no improvement on as new games are released is AI, even within this current generation. When I was younger I kept thinking about how advanced games would be in this regard 10 years into the future, enemies would try to outsmart you at every chance, encounters would become more and more unique, etc. and yet here we are and the results are underwhelming. Sure we have some rare games like F.E.A.R. with excellent AI, but overall it hasn't been great. To illustrate this point I compared a game released in 2001 to one released in 2013, and the results… well… see for yourself.

AI has seemed like it has stalled for waaay too long. Its really sad.

They can't make AI too good because then people will get frustrated and put the game down. It's actually easier to have the AI behave perfectly and they put work into dumbing down the AI to make it easier. Unfortunately that's the reality as to why.

Some of the F.E.A.R. AI was... let's say the system is easier to see when you know how it works. Because of the arena-based combat design then it was relatively easy to design "smart" bits of "AI" that were, in one way of looking at it, more scripting than actual smarts. I think it's worth playing the PS4 Killzone (on hard, no checkpoints - both options tied to trophies but doing them at the same time really unlocks a mindset that allows detailed examination of each combat arena) to see where that path of design constraints led.

Advancing AI is hard (we found several ways of getting to a roughly equivalent local maxima plateau that it's costly to get beyond - recent advances has been in dev-side so automatically generating the traversal/cover meshes for each level rather than making mappers build them in etc). The original Unreal had AI that could use the open, looping environments to react in ways interpreted by players as flanking. Quake bots, rapidly evolving into intelligent agents (that can play Counter-Strike). The original Unreal Tournament. HL1 marines. "Can route around levels using the traversal mesh" is actually a lot of the way to making AI that players think is worth talking about. From there it's more about flagging behaviour ("looking for" players can be just as much about offering an interesting puzzle for players as making them actually look - the game knows where you are and so can build a maze for you to "outwit" to make AI that feels good. That has nothing to do with making AI that realistically looks for you and the way solo players are the hero of the story means AI must be designed to lose).

I enjoyed the AI in tLoU, playing as a pure stealth player. The routes, awareness states, and so on wasn't a bad implementation. It does a lot more than just run at you (with melee weapons out). The searching, the splitting up in groups, the swarming (AIs engage at similar times from different angles). My main complaint would actually be that the arenas they did build with several stages (incapacitate everyone/alert someone and a new batch would come in) were buggy as all Hell. I got a total despawn (after the AIs basically stopped) and a double-spawn more than once. The stuck AI in the video being pushed about: yep, that's the really annoying one and I think it's from a multi-stage arena bit of the game.

God, imagine a truly challenging gameplay experience against AI that isn't built upon the AI having a cheap advantage such as more HP, XP, or damage output. Instead of relying on connecting with competent players online I could face a sturdy challenge in single player and feel like my wits won the day instead of brute force. Last time I felt that was with the Infinity Engine games, but I haven't played since I was a lad so don't know how the AI stacks up.

@shivoa: So is it only possible to make the AI seem smart through scripted behaviours? Even so, how come more devs haven't taken this advantage? Specially considering how games like Half Life 1 had somewhat interesting AI behaviour back then (even with uninteresting enemies): https://www.youtube.com/watch?v=RV9ooD5rx1o

Most games don't seem to go far from the shoot on sight, run in plain sight and hide when hurt. I mean, I get that it's hard... but it's been so many years already, is it not just because developers are not bothering anymore?

I agree that enemy AI in video games seems like it has not improved much. In fact, the AI in most of the games I play is simplistic and barely functional at best. That's why when I played the Last of Us, I was blown away by the wide range of AI behaviours. Human enemies can flank, form search parties and try to make sure their buddies are alive, and get scared when you kill so many of them. That is, of course, when the AI is working as designed. Buggy AI is one of the main problems with the combat in the Last of Us, but I certainly have not encountered anything of this severity.

The only games I can point to and say that they have relatively good AI are probably the Souls games, particularly Dark Souls II and Bloodborne. Certain enemies in these games are pretty smart and can change their play-style based on yours. Also, I haven't played it, but it seems like the AI in Max Payne seems to be fairly good.

@ericjasonwade: Thats the pr division speaking. The answear is that its cost and performamce comsuning to have ai behave realisticly.

Some mobagames have quite impressive bot ai. But ofc. They are nowhere near human levels.

Racing games is also slowly beginning to get half competent ai drivers in some games but again. Nowhere near human drivers.

@burusu A nice and interesting video. The academic in me wants to emphasize that it's not a particularly balanced representation of the two games. I.e. comical music in the background during TLoU, and somewhat derisive commentary.

Full disclosure - I haven't played TLoU - but the video does seem to indicate that the AI in that game isn't particularly advanced. The one point made in the video I still am not convinced of is, that apparently enemies in TLoU fail to respond properly when significant noise (gun shots) are made close to them? Given that to the best of my knowledge the game contains a lot of stealth sequences, I find this a bit hard to swallow. Especially when coupled with all the rave reviews it's gotten. Then again, I have never played it.

As numerous people have pointed out, making good AI is really hard. Most games that do it really well use some really deceptive techniques to make the enemies seem much smarter than they actually are. Knowing exactly what's being done can do a lot to dispel the magic.

One thing that's sometimes forgotten is the reality of resource distribution. Most of the time AI routines get a mere 10-15% of a systems resources, and despite all the next-gen claims of using the cloud to sort that out, I'd imagine this is still the case for most games. Couple that with the fact that in most FPS', the enemies generally get to live no more than 10-15 seconds a piece, it's no big surprise that this area, given it's already high difficulty, sees fairly little improvement.

I agree that AI hasn`t advanced as much as I would like it to, but I agree Gazoo that this is an unbalanced representation of the two games. As someone who has played both games (even if it`s been a little while) the examples from Last of Us is definetly the worst and most buggy parts of the AI in that game (personally I did not run into a lot of bugs in my playtrough) while the Max Payne video specifically sets up situations to show of the quality of the AI.

TL:DR I agree that the AI in Max Payne is good, but I also don`t think the Last of Us AI is noticeably worse (but also not that much better, which is the real problem).

I need to play Rage when I upgrade my PC. I heard good things about the AI in that. Or at least the movement of the AI.

There might be a misconception between two different goals: Artificial Intelligence Implementation and Artificial Intelligence that aims for some bigger than life immersion. An awesome complex implementation, with a multiagent system and maybe even a neural network that learns about the player over time, might not be fun at all for a game where you are some sort of unrealistic badass. Like in for example Far Cry 3, it is crazy to think that you might take out 5 soldiers out in the open field like that, but the game AI serves to make you feel lije you can immerses you and empowers you as a badass.

There is a lot done in the Artificial Intelligent field I think, which is great, but better AI won't make your game more fun necessarily, the developers could have a hard time controlling complex behaviour of the AI in such a way it is still immersive and empowers the player.

Personally I think AI as immersion should be the highest goal and is for a lot of game developers. Like the simple creatures in Animal Crossing, which are scripted very uncomplex but which feel a lot of fun to hang around with. I like them far more than the far more complex Skyrim and fallout AI, which are implemented complex.

Max Payne is a fantastic game, so there's nothing weird about this.

The Last of Us was my favorite game of that year, easily, but I will say there was a bug with the A.I. (I never got this far on the Remaster, but from what I remember it was primarily a graphics job) that infuriated me a few times. It only occurred during and after the Winter chapter, never before. I would die and upon respawn enemies wouldn't be walking their general patterns, they'd be in full alert mode and in some cases even actively aware of where my character was. Sometimes this made encounters so hard I was better served re-loading a save and trying to get back there without screwing up the way I had before.

Being a mostly stealthy player (and finding several of the final encounters fairly challenging as a mediocre action gamer) made that really frustrating, and actually made the last encounter a trial in breaking the game rather than out-smarting the A.I. I essentially did a mad dash from one end of the map to the other and then essentially re-broke the A.I. by exploiting the environment and their mad cow-like behavior. I believe this is related to what @shivoa was writing.

If I were to rebut some of the video's issues I would say that:

1. Last of Us is primarily a stealth game. The bulk of a AI programming is large on the stealth behaviors I imagine. Different awareness states, sight lines, responding to player behavior as well as clicker AI, thrown objects making sound, player making footstep noise all factor into AI design. Not to mention this guy is comparing AI of two different genres of games which seems pretty BS to me.

2. Enemies run at you. They run at you when you're found. I also felt like they flank you, I don't have video to prove it but it certainly seemed to happen time and time again when I played it. So yeah, they run at you. It makes sense to me because there are so few guns in this world, they're gangs rather than militia or mobsters. Starving dudes who want to take what you have. Also the gameplay is designed around ammo conservation. If you just pull out a shotgun and blast every guy who runs at you you're doing it wrong and will very quickly be out of ammo. It's also effective. I got killed many times by those guys mobbing me.

3. Maybe AI hasn't changed a lot because simple AI is predictable and games rely on known behaviors. X-Com had incredibly predictable AI but that allowed calculated decisions to be consistently made on the player side. And it's a game VERY much based on how enemy encounters play out, even against a single AI.

4. I didn't run into any examples of that kind of AI behavior in The Last of Us. Not once. Seems the video maker has it out for the game.

5. Max Payne is awesome. But it's bullshit that guy got him when he came around to shoot him in the back, "all knowing" AI is some of the most BS in gaming.

Should be worth nothing that despite loving the hell out of Max Payne, the AI in it is not even good, which makes this video even harder to stomach.

@dudeglove:

Somebody else that actually enjoyed FC2 as well? Jesus, I thought I was the only one, but you're right, it did a lot for its time and its still somewhat impressive to play nowadays.

Considering the amount of bullets the player has in that video, I can only guess it's on a lower difficulty. TLoU on harder difficulties is absolutely brutal and punishing.

I remember Blizzard did a presentation about Diablo III AI. They demonstrated the difference between making really smart AI and enemies that are fun to fight. Looked like it took even more work to make them LESS deadly.

I distinctly remember not meeting the minimum requirements for Max Payne 2 and it still ran super well on my terrible computer. I think it probably had something to do with Remedy being founded by some people in the demoscene. How well a game runs doesn't necessarily have anything to do with its AI but it seems to me like a group of coders who took the time to make a game that ran so smoothly would probably enjoy coming up with a few tricks to make the AI interesting as well.

I think that's doing a huge disservice to The Last of Us, because it depends on where you're at, and the thing the enemy has equipped. I find that AI to be very impressive, and a lot of the time, easy to go about the environments and catch one off guard when things are going on, so you won't always know where the enemy is at, especially in the specific video shown above, though like any game, a way can be figured out to exploit a section. Max Payne on the other hand was and perhaps still is impressive, but to say it's better than The Last of Us would be incorrect I'd say. The way battles can go in different ways as the AI try to outsmart the player in The Last of Us is one of its strengths. The video shows it incorrectly. Plus, it's a bit hypocritical.

im no programmer so when i say this take it with a huge scoop of salt. But after reading most of that paper from fear i kind of assumed most ai in the vast majority of games works on motivation>action>goal> if success then yay, if failure, repeat step one.

Is that not how human beings work? we walk into an arena. we see bad guy in red. our goal sis to kill said guy. we then make hundreds of tiny decisions and compute how to achieve that ultimate goal of killing the bad guy but surviving. We think about our weapons and its strengths, we consider our hp, dmg output, speed, environment, react to the enemy- literally tons of things you dont think about until you take a minute and deconstruct a battle. besides all the technical challenges of ai and its scripting, i just think ai isnt a big thing anymore. more and more games are putting more emphasis on online and servers and matchmaking. lok how driving games are using "drivatars" now instead of doing a full on ai race with 16 bots. and some of the bigger games that do focus on ai have these big cinematic set pieces that they almost have to dumb down the ai to fit with what they want out of a set piece.

Has ai stagnated over the last generation? yes of course. but i think it will improve until skynet takes us all out like roaches. kidding aside, i think once we reach a plateau of diminished returns in graphics, hopefully more and more devs take ai on full storm. cuz i have always imagined an ai that learned and kept track of its encounters with the enemy and was so dynamic that it literally pushed the players limits. instead when i encounter a boss thats hard to beat i try to think about what the dev wants from me. "do they want me to use a certain mechanic? is the hit box at a certain location? is the boss going to come at me with attack 1 attack 2 or attack 3 this time? etc" give me a living breathing ai that isnt just a bot with 3x hp and a bazillion dmg output. Interestingly enough, there will be a point where ai cant be too good because thats not realistic either. its like when you play those COD coop modes on ultra hard mode and the enemy will head shot you in .1 second just because it can turn at the drop of a dime.

its hard for me to bitch, just because i know im now the one to make this super advanced ai. In fact, i always wanted to make my own game but ai has intimidated me so much that i doubt ill ever make anything more than a rudimentary pong pos.

EDIT: You can bash TLOU all you want but i thought the ai wasnt terrible at all. i never encountered any of those bugs you saw and thank god or i would have hated the game. if anything, i would complain the game design of naughty dog's hero being a mass murder and escaping all of those encounters alive. but whatever. i enjoyed the game for what is it! to each their own. thats what makes game great!!!

IS that music from Persona?

I agree. The environment and the simplicity of the goal was incredibly immersive for me as well. I even liked the malaria mechanic and how it forced you into continued interactions with the locals.

On topic: It's not really an AI procedure but the fact that the enemy restocked outposts quickly after a mass murder occurred added to my immersion and illusion of artificial intelligence. Almost everybody hated it, but how can we improve AI when something as simple as "sending in reinforcements to retake an outpost" get's nigh-whole-heartedly panned by the vast majority of the community?

Even if the enemies crouch and dive more realistically, I'll still have a hard time buying it if the overworld doesn't reflect a greater sense of AI.