Well, here we are, March 27th, 2011, only 5 days after the release, and the verdict?
The AI isn't as amazing as it should be (though it's an improvement over Crysis 1's AI).
One problem the NPC System faces is that the NPC's go down after you hit 'em, but get back up. IT annoys me, because I move onto other people once my enemy is down. They suddenly get back up and attack me!
Indiviual NPC's will simply keep their idle stance when someone goes down near them (sometimes, they go to investigate, which is cool). Any NPC's in vehicles? They don't shoot me.
Atleast the AI doesn't suffer the 'no-shooting, but staring' syndrome when you were uncloaked in Crysis 1. In Crysis 2, they sometimes notice you a little too fast, but this super-vision is better than 'shock-vision'. I'm happy they were able to solve that.
The AI doesn't shoot at you while you're cloaked, like in Crysis 1 (unless you're too cloaked). That's great. it annoyed me that the Vehicle Gunners in Crysis 1 were able to do that.
Considering that the game is a "Linear Sandbox", where you're forced to go to an area, but the area lets you complete something in a Sandbox-y way, the AI must have been hard to code, again.
The Difficulty of the AI? Magnificent. They were very awesome at running around, which made shooting them hard, (though that's partly because of the gun mechanics), and they did take cover, because there was alot of cover put there by the Devs. Their numbers made the firefights very engaging, because you'd be losing energy, and trying to keep that health up. This is on Hard, and I'm not sure about the lower difficulties, though I'm sure that Super Solder (the fourth level) will be devastatingly lethal, in terms of damage by the AI.
Crytek did promise many dfferent death sequences with each NPC, right? I don't see much difference, especially for the Alien NPC's (the DUMBEST, for god's sake). The Human NPC's seem to always clutch their neck when I hit them around the shoulders, or upper-chest. I wish they'd make their hand go to where a bullet hit them!
(That'd be cool, anyone know a game with that?)
I just didn't like that Mr. Yerli (Crytek CEO) said that Crysis 2 would have the most advanced AI you'd see. It didn't really improve much over Crysis 1, if you look closely, but it satisfied my gaming experience. I don't expect AI to be "realistic" yet, I'm expecting that for the future. Maybe around 2060? We might have some unbeleivably great AI to destroy.
They simply need to fix some glitches, which could even be in the process right now. (There's been two patches so far, 1.1 and 1.2, in 5 days after the release! Imagine the game after 1/2 months, almost 0 bugs in physics and AI. Then, the game will be unbelievable.)