If you haven't played Meat Boy yet, you definitely should check it out on New Grounds. The game is an odd-ball 2d adventure, and is set to be released with redone graphics and gameplay as a WiiWare title. There isn't much to say about this title except that when it comes out, it will be insanely popular.
Essentially the game is like N+, with a zanier premise and more mature. To be blunt, blood is splattered everywhere when Meat boy runs around because guess what? He's a glob of red meat!