Enemy AI is a difficult subject to tackle in video games. Some may argue that current tech isn't advanced enough to implement ultra realistic AI. However, in a world where your phone's AI can book appointments for you, can't it spot a hooded figure hiding in a 'crowd' of four people? In fact, the AI in 2006's The Elder Scrolls IV: Oblivion was so smart that the developer had to 'dumb' it down for the final release.
The story says that each of the thousand NPCs had their own needs and wants and that was what determined their routine for the day. One story often told is that one NPCs AI determined that it was time to rake the leaves, only the nearest rake was in the possession of another NPC. So the AI determined the easiest way to get it was to murder the NPC and take it from his corpse. Five minutes later the player wanders in and there's a dude raking leaves and a corpse in the corner, the player wondering what the hell just happened.
Hence, AI is a tough nut to crack. Make it super realistic and the game won't be fun anymore as it's too tough. Make it too dumb and, once again, the game won't be fun anymore but this time because it's too easy. A "good" in games are not "good" AIs, but an AI made to look good or simply put.
Now we know that AI is difficult, let's add the dynamics of the open world to make it a bit spicier, like a fended environment such as the spaceship from the Alien Isolation. Simply put without diving into the logic of the AI, the Alien AI was familiar with its surroundings and knew what to based on limited user inputs. However, in an open world where there are multiple approach angles, many ways to infiltrate and various approaches to eradicating your target, a "good" AI is all the tougher to achieve.
Today, we're discussing the top 4 open-world games that nailed the AI component.
4. Assassin's Creed Rogue
Assassin's Creed Rogue is one of the best Assassin's Creed game that has been forgotten over time. While Assassin's Creed Rogue's story was cannon, the game was never considered a part of the main series. Assassin's Creed Rogue is often viewed as a "substitute, second class" game for Xbox 360 / PS3 with reused components from Assassin's Creed Blackflag, bred in the shadows of Assassin's Creed Unity.
While the naval combat may have been a clean copy-paste from Assassin's Creed Blackflag, Assassin's Creed Rogue featured the best enemy AI out of any Assassin's Creed game to date. Since you were playing as a templar fighting the Assassins rather than the other way around, all the 'cheap' tricks that you used as an Assassin were played against you. That meant that enemies were hiding in plain sight, blending in crowds or sitting on benches. On top of that, if you somehow led an Assassin faction to a templar battalion or vice versa, they would engage in full-on combat. You could even find such disputes in the open world and it was up to you to interfere.
I believe Assassin's Creed Rogue was Ubisoft's answer to the jokes about "How could that templar not see me?!" Point proved, you and your awesome AI win Ubisoft.
3. Shadow of War
Enemy AI was such a central part of the Middle Earth: Shadow of War that they decided to give it a unique name, the Nemesis system. The Nemesis system was an intricate AI that generated the ranks of Sauron's Army and filled them with randomly generated orcs. Each orc had a unique skill set which was reflected not only in their appearance and weapons but also their names.
If you killed an orc in the army, the Nemesis system will replace it with someone from the lower ranks and the new orc will power up. When you progress through the game, you gain the ability to dominate orcs who could either fight for you or work as a rat in the army, supplying you with crucial info. Not only that, but the orcs had independent routines and rivalries of their own. If you learned about their routines and rivalries, you could use that info to your advantage by either ambushing them or dominating them. Some of the orcs had the ability to overcome their dominance or betray death, and that would be reflected by their appearance as well.
Shadow of War's Nemesis system actually made you feel like a great battle tactician, a mark of a great AI.
2. Metal Gear Solid 5: The Phantom Pain
Metal Gear Solid 5: The Phantom Pain is Hideo Kojima's final touch to the series he nurtured since its inception. Metal Gear series was always above its competition when it came to AI, but the Phantom Pain took it to the next level with the Revenge System.
The Revenge System was all about enemy soldier's preparedness that altered based on your actions. So if you infiltrated at night, the enemies will use floodlights and night vision goggles. If you infiltrate via roads, there will be more checkpoints along the way. If you snipe a lot or take too many headshots, the soldiers will start wearing more armour. If you sneak a lot, the enemy base will be equipped with cameras and even gun cameras.
The world of Metal Gear Solid V is full of these nitty details that feel simply organic as if that would be the natural response of military holdouts. That's what makes it a great addition to our list of the best enemy AIs.
1. Red Dead Redemption 2
There are two things that make a game realistic: photorealistic graphics, obviously, and an 'alive' world AI. Red Dead Redemption 2 nails both of these aspects.
We'll come back to the enemies in Red Dead Redemption 2 in a bit, but first, let's talk about the world. The world of Red Dead Redemption 2 does not revolve around you, which means every NPC has a life of its own. If you follow an NPC around in story mode, you’ll see they have a daily routine and jobs they work in. It's not only true for major NPCs like John Marston and Bill Williamson but literally every NPC in the world. One instance is a person who takes a stagecoach from Carmody Dell all the way to Blackwater and back every day for farm supplies and trade. From time to time, NPCs will come and talk to you, sometimes it's just gossip while other times they may need your help. They'll comment on your clothes, beard and hair. Major recurring NPCs will also talk differently based on your prior interactions and if you engaged in any side quests with them.
The AI is not just limited to human AIs but extends to animals as well. You can find bears feeding on carcasses they hunted or wolves hunting stags. If you let a Grizzly Bear in RDR2 approach you without moving your character, the bear will roar and attempt to intimidate you. If you remain still, the bear will give up and walk away. This is actually documented behaviour of real bears when they perceive their prey to be defiant.
Then there are the enemies, who are equally as impressive as the rest of the world. If you try to pull out a gun in a hand to hand combat while you're too close, they'll knock the weapon out of your hand. Enemies will duck behind cover if you're using long-range weapons. Your hat will drop in combat.
All of this makes it seem nearly real with the attention to detail Rockstar put into the game