When the first one came out I played a bit, never finished it.
Then Warhead came out and I got the package on Steam, Crysis, Crysis Warhead, and the other online Crysis game. I played through both in order, it was awesome. My system has some issues playing them but was a great game.
Though don't play them now, online FPS games don't interest me that much these days. Only certain ones.