The AI has been drastically improved, and the player's team will adapt to whether or not they are seen by whispering. The AI also makes mistakes such as tripping, and helps each other when these mistakes are made. The enemy AI has also been improved allowing the Germans to counter your actions. The game is built on the Unreal Engine 3 and the Windows version can take advantage of the features in DirectX 10 which allows for an enhanced graphical experience for more realistic gameplay.
The game is amazing, personally, I've never seen any of the AI tripping, the multilayer feels like a free download. And a crappy one at that. But the single player is definitely worth the money, or at least, wait till it drops to 30. I hope to god they fix the multilayer.... or is this article about a mod?