I won't go over anatomy stuff, cause Carl did an exhaustive rundown already, but I will note something that I think is pretty major... dudes got no skin! You can clearly see the separation of each muscle, and it's insertion and origin. It's like looking at one of these
instead of one of these
Remember that there's always a layer of skin, and, in this case, tights, that will soften the connections of the muscles. Having a knowledge of anatomy isn't just about knowing muscles, it's also knowing what you can leave out. I'm sorry if it isn't clear what I mean, I can do a draw-over if that will help.
The other thing that bothers me is that he's very ugly, in the face, that is. I don't mean to be harsh, but there's no two ways about it. If I saw this guy on the street, I'd turn the other way.