The AI is better than in the first because it starts on AC1 code + improvements, more reactions, more detection, etc.
Also, AC2, like GTA4 or again Oblivion are some of the most AI advanced games of this generation. I don't know if people understand what AI is. Or I don't know if they realise what is governed by AI in a game really. If you isolate a character and think about it, of course they will look stupid... just like in GTA or Oblivion. The thing that is impressive in that type of game is that there's alot of different AI that actually interact with each other and/or also work in group. In AC2 you have the crowd (individual or in group) + friendly NPCs (mercenaries,courtesans,thiefs - with all their different approaches) + militia. Now all those work together, have reactions, detection and whatnot. Don't forget all the player induced stuff that is even more than that. Also, the militia is the most advanced AI. They work solo, in group, in interaction with other groups like crowd and friendly npcs, to smokebombs, poison, pickpocketing, dead bodies, they detect, search, talk, attack, pick up weapons if need be, throw rocks with aiming, and ALL the fight stuff with also takes coordination and tons of reactions with the player and other fighting people. They can also detect and run after pickpocketeers.
I don't think people realise that this ENORMOUS amount of AI processes is all there in the memory, ready to be called and + a damn lot of it at the same time. Reality is that what is taking the more juice in this game isn't the graphics, the lod system, the texture or the sound, it's the AI...
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