Err, well, I know it's a choice of style, but your guy looks very 2-D in a skewed kind of way. For example, his upper body is incredibly thin, and in a bit of an unbalanced way, it is as if you didn't want his left arm to cover/obscure his body and made it very thin as a result, and so on. His butt(sorry) is also very thin, and for it to connect with his legs would have to make them very thin and so on, etc..
So even if your idea was to make him thin, I don't really buy it. D:
Fatten him up, think of how he and his body parts would look from different directions, think in 3D, you know? You'll have to trick the brain of the viewer that you guy actually would be able to move and almost exist for real (a very obscure real is okay too)..
You don't trick my brain yet, though D: That's all. Sorry if I can't give better C+C, and please don't get mad at me :]