Many game developers intentionally make the AI in their games easy to deal with. Only a few choose the hard way and try to challenge their fanbase by making AI behave in more inventive ways than just duck, dodge, fire.
And of course, every gamer has his or her own favorite titles, but these nine games are universally praised for offering something new in the department of artificial intelligence. Each case has its own peculiar approach, and each shows just how deep one can dive into the possibilities of machine psychology.
Different genres of games utilize different algorithms when it comes to programming AI. For example, FPS games implement the layered structure of the artificial intelligence system, while RTS games have several modules, such as effective path-finding, economic structuring, game map analysis, and more.
You will learn about all these different algorithms in the list that follows. Let's get started.
Developer: Monolith Productions
Release date: October 17, 2005
Platforms: PC, PS3, Xbox 360
If there was ever a good AI in any FPS game, it was definitely the one in F.E.A.R. The enemies would never act in the same way, but they would react to each other’s situations and would never repeat the same mistakes. This prompted players to constantly change tactics and never sit in the same position.
Here’s how the designers of the AI have described their approach to F.E.A.R. (read full statement):
“In F.E.A.R., A.I. use(s) cover more tactically, coordinating with squad members to lay suppression fire while others advance. A.I. only leave cover when threatened, and blind fire if they have no better position.”
On top of that, enemy AI always applies pressure -- at times, you don’t even have the time to heal. The harder the difficulty you choose to play, the better the AI behaves.
That's not to mention the weapons physics and movement animations in this game were groundbreaking for its time.
Developer: Naughty Dog
Release date: June 14, 2013
If you’re wondering what this game is doing here (since the enemy AI in TLOU isn’t much to write home about) it’s really not about enemies this time, but instead about a companion AI -- Ellie. The teenage girl, the key to the survival of all humanity, is the star of the game, and it’s mainly because of an excellent AI.
Did you know that the release of TLOU was initially delayed for five months? The director of the game decided to overwrite the entire companion AI from scratch. Well, it’s a good thing that he did, because Ellie has become a true friend and not just another burden on your hands.
Here’s what Naughty Dog's Max Dyckhoff said about Ellie’s AI at GDC 2014 (watch the full presentation here):
“Much of this was built on simple ideas, such as how to decide where Ellie should stand: the basic mechanics decide a zone she can inhabit, then draws a series of lines between her and Joel, the direction she's looking in, and where she could potentially move to. If any of those lines hit a wall or obstacle, then Ellie can't stand there.”
Developer: Ubisoft Toronto
Release date: August 20, 2013
Platforms: PC, PS3, Wii U, Xbox 360
The objectives in all missions of Blacklist are basically the same -- avoid guards at all costs. You got it right -- it’s a hard stealth game. The guard AI is truly something here, and generally speaking, the AI in the Splinter Cell series has always been a subject of fascination.
It reminds me a lot of a chess game. You enter an area, detect all the guards, figure out the plan of evasion, and move forward to a complete execution of the mission. But it’s not as easy to do as it sounds. The guards are programmed to detect and react to the smallest things -- not just visual cues, but audible ones as well.
On top of that, they have dogs that prowl in the most unexpected corners, forcing you to reveal your position. It’s really something, and people have been writing entire essays on just how good the AI is in Splinter Cell: Blacklist -- you can read one of them here.
Developer: Firaxis Games
Release date: October 9, 2012
Platforms: PC, PS3, PS Vita, Xbox 360
Alien AI is the reason why the reboot of the XCOM series succeeded back in 2012. And the person responsible for that AI was Alex Cheng, who decided to make the AI not just distinctive, but also entertaining.
This effect was achieved “by means of a utility-based system -- a system that gave a measure of 'usefulness' to every possible action.”
And this is what XCOM is known for: its limited system of movement that requires the AI to calculate the most efficient way of action for each of its turns. It would consider everything, such as the distance to the closest objective, proximity to other aliens, the number of enemies, the behavior of the enemies, and more.
This approach to AI is truly groundbreaking and should be taken into consideration by other aspiring video game developers.
Release date: September 14, 2010
Platforms: Xbox 360
Halo: Reach stands out from the rest of the games in the cult series from Microsoft due to its staggering AI. This statement regards the Elites, who are some of the smartest and most aggressive enemies you will ever encounter in a video game.
One could re-play the campaign over and over again without ever getting bored because the AI would behave differently every time. When the fans figured this out, they decided to push the AI in the game to its limits. And thus, in 2011, a team called “Termacious Trickocity” recorded more than 150 hours of gameplay in an attempt to show just how good the AI is in Halo: Reach.
The result can be seen in the video above, which is a 10-minute montage of the best moments from the entire Termacious Trickocity run. One of the members of the said team, Aaron Sekela, stated the following:
“Our hardest trick though would probably be the ‘Exodus Marine Collection.’ That’s the trick that starts around the 5:48 mark and ends at the 6:29 mark. We were in that game for 7 hours, getting the marines to cooperate was extremely annoying, we had to make sure they didn’t get killed by enemies or being launched over the river. Once over the river we need to drive 10 minute to get the marines, to the top of a huge mountain. We had to go back and forth about 4 or 5 times. Lack of check points didn’t help either.”
Developer: Ubisoft Montreal
Release date: October 21, 2008
Platforms: PC, PS3, Xbox 360
It is a sad thing to say, but the Far Cry series doesn’t get any better with every new installment. Ubisoft tries to appeal to a more casual player these days, but at one point, Far Cry was one of the most unforgiving games ever made.
The first one was developed by Crytek, and then Ubisoft helmed the second one, and the rest of them followed. Far Cry 2 was so challenging that people went as far as calling it “sadistic”… and it was for a reason. The enemy AI was simply brutal, and there were no friendly NPCs -- everybody was hostile.
There was no real system to the AI’s behavior -- it was just incredibly chaotic and unpredictable. This alone made the game super hard, even for veteran gamers.
Developer: Blizzard Entertainment
Release date: July 27, 2010
Long-time SarCraft players may laugh at this suggestion, because even the Hard and Elite AI in StarCraft II is not too impressive. But again, this is the case if you’re an experienced player. However, if you’re just starting out in the StarCraft universe, playing against AI is your best option, and it is built exactly for that reason.
The AI in StarCraft II follows the same sequence every time, which is perfect for learning and developing your first strategy against it. Later, when you know what you’re doing, you can start playing against real players.
And the last cool thing to mention is the upcoming StarCraft II challenge offered by the British AI developer -- DeepMind. It’s the one that beat the Go world champion last year, and it would be really interesting to see how this intelligence will fair against Blizzard’s own AI sometime in 2017.
Developer: Creative Assembly
Release date: October 7, 2014
Platforms: PC, PS3, PS4, Xbox 360, Xbox One
You would think that the true star of the game is the main character, in this case Amanda Ripley… but no -- it’s the Xenomorph. This creepy alien and its constant, looming presence throughout the entire game makes it a particularly interesting case for an enemy AI study.
This kind of prolonged interaction between the protagonist and the antagonist is unprecedented in the world of gaming. It probably took a lot of effort to program the complex behavior of the creature that would jump out of the most unexpected places.
Clive Gratton, technical director on Alien: Isolation, said the following about the multi-layered AI system (read the full interview here):
“Our basic premise for the AI was ‘not to cheat’. The level is pre-processed to find interesting places for the Alien to search. We then drop it in with a few parameters to say how fast to search, where and what size radius. If the Alien hasn’t spotted the player then it’ll do a leisurely search of a large area. If you can hear the Alien in the vents close to you then there’s more chance that it can hear you and will come down. It is actually traversing through the vent network.”
Developer: Bohemia Interactive
Release date: September 12, 2013
ARMA 3 is known for a super precise enemy AI. Ever heard of clear shots on 300 or 400 meter distances? Yep, that’s ARMA 3. But many people don’t know that the best thing about the AI in ARMA 3 is that it is fully customizable.
If you know how to edit “.ini” files, then you can easily set up the game’s AI to your liking. On the other hand, you could just download and install one of the many AI mods that are freely distributed for the game.
However, most players have adapted to the default settings, and show no mercy for their enemies.
What other games do you know of that possess a great AI? Share their titles and leave your opinions on why you think so in the comments.