Mmmmn, nice. I suppose his shoulders should have something going on, one being higher than the other, depending on how he's holding himself, perhaps his hand should be bigger.

.... It's purdy, though.

(Lack of nipples is a common complaint at Shirtless Superheros (http://shirtless-superheroes.blogspot.com/). I recall one post praising one artist for both drawing including them while leaving out a lot of the details, something that's not easy)