Thanks for your comments.
Yes, the proportions seem to be the main problem.. I should have noted that it isn't the goal to create a very realistic model. Nevertheless, I think we might have to rethink the artstyle, and choose either strictly realistic or overdo the proportions a bit more so the proportions cannot be mistaken for bad modelling. I'm thinking big hands, big feet - fable style.
The head was modelled from reference photos but I see what you mean, Frank. It might also be because the texture has a smooth-skin texture on the head which doesn't look very natural but there will be several hair models that fit on the head, this isn't anywhere near the final look.
Oh and anonymous_alcoholic, ofcourse I don't want to have only stereotypical muscular-superhero models in my game so I think my next work will be inspired by this one:
Image

BTW, apparently some people don't apreciate me posting here since I got rated down, lol.