wow, the jeans look great.  The torso and hair don't look quite as "finished", and his left fist has a slight readability issue.  At first sight it looks as if his wrist and hand is bent completely backwards, and his fingers are pointing to the right.  Maybe move the curl of the fist more to the center, and shape the fingers a tad so they are more noticeable and not just a small rectangle

Edited by Frost Butt - 20 October 2011 at 12:30pm

Here are some more ideas.  I softened the outlines of the flesh and hair.  I also changed the eyes up a bit - the full black lower lids seemed a bit heavy.