Crysis 2. Just beat the first one and I really liked it, but this seems like massive decline all around. I knew going in it was a different beast and I can stomach a console-y linear setpiece shooter, but this game hasn't done anything to distinguish itself yet. Hopefully it improves.
Don't get your hopes up. Crysis -> Crysis 2 is one of the worst examples of decline I can think of in that genre.