"Here is the issue. Let me start off by saying that the game is amazing, but after reading all of these reviews I am becoming more and more frustrated because the people giving this game a 10/10 have over looked something extremely important.
The amazing "next gen" AI that Naughty Dog have been advertising can be seen in how the enemy reacts to the rest of his friends getting killed in this video. http://www.youtube.com/watch?feature=player_detailpage&v=qguDnY0C_Sg#t=721s
Another example is how human these guys act in this video http://www.youtube.com/watch?v=kbLOokeC3VU
So what is my problem you might ask? This crazy human like AI is almost non existent in the actual game. The AI is virtually no different than Uncharted. The guys will just run at you with their bare fists even if you are pointing a shotgun in their face.
The enemy NEVER tries to post up in a room and ambush you, they definitely NEVER run away and hide to preserve their own life, and they NEVER beg for their own life after being beaten to the ground and having a gun pointed in their face. So I have to ask, why was this issue completely overlooked by those who reviewed the game?
The only part of the AI that I have actually seen working in action is how they freak the hell out when you take one of their guys hostage, they rarely respond to hearing you try and fire an empty weapons, and they do sometimes flank you. Nearly everything we have seen so far concerning the human AI in this game has been completely misleading. It's apparent to me now that everything we saw at E3 was completely scripted and the AI we were shown at e3 is not the same that is in the full game..
I'm sorry if this seems like an over reaction, but this awesome human like AI was a massive selling point for me and I am beyond disappointed to see that none of it ever actually existed.
I just want to make this completely clear. I'm not saying that the AI is bad or completely retarded to where it ruins the game. I'm saying that what we were presented with at E3 is not what you are going to get when you pick this game up from the store."
Source: http://www.reddit.com/r/Games/comments/1fuez8/so_i_have_been_watching_my_cousin_play_the_last/
I think this is an interesting read and may be worth a little debate. Enjoy^^