Far Cry was great up until the rocket launcher guys. That was what broke it for me. Although having auto-saves when I had no health, no ammo and a monkey in mid-air a foot away from me was also frustrating. Ha, I remember how irate I was over the auto-save system.
Crysis was great, too. The free-floating section was awful, but I didn't much mind the aliens afterwards. The game had a few incredibly tense moments for me that I vividly remember, much like in Far Cry
Warhead was pretty much just Crysis, and I still really dug it.
Far Cry 2... I dunno. The graphics felt off to me and I couldn't put my finger on why. It's yet another game that I barely made it past the tutorial part. First it told me to buy something from the weapons dealer but he wasn't there. I thought it was a bug, and I kept logging into the computer, but it turns out I needed to do something on it I was missing (I think I needed to buy something I was missing.) That whole experience soured me, I went into the town, got into a fight there, and ended up deciding there were better things to play (I think DX:HR came out just then.)
Haven't played Crysis 2, but maybe I'll grab it for $5 on Amazon. Want it on Steam, though. Is it even on Steam?