I feel the same way, the more I play the crysis demo and get distracted by other new next gen games, I just feel that crysis is just at a new level of immersion. This is not due the graphics its mainly for physics and the sandbox type gameplay. There is just so many options to do things, its almost like a strategy game mixed with a FPS and some RPG added for good measure.

I actually have to think about tactics and strategy when I play single player, sure the AI might not be as Phd smart as Crytek talked about but they are not totaly scripted like other recent games.

Its like a new genre of FPS. I really hope we get more games like this. Lately we have had few advances in how FPS games play. Its all the same run and gun action in diffrent forms. Crysis and Bioshock tries to change this, Bioshock with its story + new gameplay and Crysis with its advanced game engine and full physics.