I'd recommend the 1st Crysis here mate. It's a lot more linear than a lot of responses in this thread suggest but it deals with that well, don't let that put you off. Also the the vehicle sections are extremely optional, not the turn off they sound like. Personally I found the game most enjoyable on the hardest difficulty, combats flows so much better that way.
The game is exceptional and definitely a must for any avid gamer's library. Go ahead and make a purchase man!
The game is exceptional and definitely a must for any avid gamer's library. Go ahead and make a purchase man!