I can see how some people could be intimidated by the latter third (and lets be fair here, what you critisize is at least two thirds through the game), but I I liked the whole game actually, that's just me. It's pretty short yeah, but has a pretty replayability value IMO, especially when you purchase a new PC whenever that is. MP is fun but nothing striking. An experience as good as Crysis shouldn't be skipped on grounds of it being "short" anyways IMO, and I'm quite confident that most people prefer shorter but sweeter games to longer and more boring/repetitive gameplay in any case..
Grey I can't believe you let the screamers scare you off this game; the sceptical ones will almost be the most noisy you know. This game is not flawless but an absolutely fantastic experience nonetheless.. was for me at least and I know I'm not alone with that