I just finished Singularity

One of the overlooked games of 2010, I think. It has elements of Dead Space and Bioshock in terms of the game world feeling. Gameplay is pretty fun, although it doesn't depart much from your standard FPS. The time control element is fun, but would have liked to have seen more applications of it.

The game does a nifty job of playing with the time paradox - changing a thing in the past that will completely change the present. There are little clues about what affect this is having all over the place within the game. There's also a nice LOST easter egg towards the end of the game.

It's definitely worth renting. I can't tell you about the MP option since I no longer do online multiplayer.