Anatomy is an issue. But first, the background looks icky. It looks as if you used some type of MSpaint spray paint tool. I personally never use it, and have never found it useful...ever( too noisy, too random for my tastes). If dots are what you are looking for, why not invest it in some nice, clean dithering, instead?
The anatomy is still off. His head looks strange, as his eyes are huge and lower than the average, invisible plane that most human eyes rest on. Also, his body seems fairly square. Take a look at your own body in the mirror, notice that even men have curves, no matter how beefy they are ( don't think highly of you physical state my friend, I'm speaking in general terms of male anatomy, heh...). I would also not try to make each individual abdomen muscle and pec an exact geometric block. Once again, we are human, and symmetry isn't that natural (most of the time...) with most muscle groupings (that is unless your a very good body builder who knows exactly how many reps his body needs to be symmetrical, which is one of the things that judges look for in body building comps...which further explains that symmetry isn't found naturally most of the time...) Not to mention, his forearm is fairly long. Longer than normal, actually. And it looks as if the wrist band is breaking, or bending his wrist bone. Light source is ok at the moment. However, his hair seems to be missing some of the reflecting light though.
Whelp, this still seems to be in the rough stages of development, so I'll crit later on when improvements are made. Good luck!