When Call of Duty: Ghosts was first announced, the developers made a joke about fish AI and how they swam out of the player's way. They were ridiculed for saying so, even though it was a joke.
The reality is that Ghosts comes with AI that makes it better than any of its predecessors in the series, in that enemy combatants are equipped with situational AI that makes them behave differently towards the player depending on context—instead of simply hiding behind walls and shooting at the player.
Infinity Ward's Mark Rubin had a lot to say on the matter.
“They might behave differently to the dog,” said Rubin in an interview with the Official Playstation Magazine. “Or behave a little differently compared to the events that are happening in the level. They take some of the environment cues and pay attention to them. A lot of times they just kind of ignore the environment, they are just like ‘Ok this guy is supposed to be here I’m shooting, but the building is falling all over me… No, I’m still shooting you’. So sort of doing stuff like that”.
Rubin said that despite the strides they were making with the game's AI, some of its development is being held back by the lack of final hardware for next-gen systems.
"We are making big strides. We need some hardware, some finished hardware, before we can really expand."
Source: OPM
