You are too fat but it has nothing to do with the game.
I finished single player. Will be looking for some co-op fun. I thought that the single player, while a lot of fun, was way too short. Hoping the co-op makes up for this. Loved the new additions (blue, red and white goop) and the tractor beams. I didn't think that the levels were all that hard though. I was only seriously stuck on one level for a while. Good story and great ending.
Overall grade for me is B+ based solely on single player play. Would have been an A if was a tad bit longer and harder.