I just finished Crysis. Damn I feel bad, I wanted to be longer. This game is awesome. It somehow reminds me about Delta Force ( ?!).
Played it on normal difficulty, even so it's somehow hard. The last part of it was full of saves and reloadings , until a text appeared on the screen : "Tip : You can alter the difficulty from the options menu" or something like that. But I kept playing it on normal :))
My system lets me play it on 1280x1024 , medium settings with high here and there ( like sound, volumetric effects etc), dx9 at a fps between 30-42.
I'm trying to figure out how to install dx10 on windows xp, I heard it's possible ( yes I have a dx10 compatible card...)
And hey, if you want more Crysis there's an expansion for you to play too.