I would like to address a concern with the game-play basics in the PC version. In Crysis 2 I noticed several bugs with the keyboard (my keyboard works fine btw). The most obvious one, is probably sprinting: If you press "r" (reload) while sprinting, you stop sprinting. In order to start sprinting again, you have to release the shift button and then press it again. Now this is very problematic if you are like me, and use mobility as your biggest strength. Simply put, pressing "r" should not make you stop sprinting. Also, this bug does not exist in games like Battlefield 3, Half Life 2, etc.
Another bug I remember are when you press TAB to see the scoreboard, and you cannot move or look around when doing so. Very annoying...
There were some other game-play bugs as well, though I don't remember them at the moment (Long time since I played Crysis 2). These kinds of problems seems to be very common with multi-platform games (and console ports). I really hope Crytek will fix this in Crysis 3, and of course give us the option to disable mouse acceleration and choose FOV (I use 90).