His left arm seems longer and larger than the right.  I'd suggest more contrast and hue shifting, with a better defined light source, as shown in this edit:
http://i57.photobucket.com/albums/g209/phototekcub/thug.gif
I meant to post this much earlier, and do more with it, but I had my own art to finish, sorry.

the biceps look a bit off if you compare them to each other since the arms are at the same angle, but still good job on it as a whole

Your best so far, great job.