As far as critique, I think his left ear (picture right) is a little misshapen and the angles of the two ears don't really seem to correspond, which is confusing. Your depiction of his right (picture left) forearm is a little messed up, too--even though from that angle the arms should be roughly the same size and thickness in appearance (if not the one further back a little smaller looking), the one furthest away from the camera actually looks larger (and slightly longer) than the one closer to the camera.
Also, I'm not totally sure, but I think the rendering of his torso might be a little off considering the angle--you should mostly see the whole thing in profile view, but the breast area appears to be defining some sort of middle points that leaves both viewable. I'm not 100% on that though; it could just be the way the shadows were done.
You did a really nice job though! You definitely know how to paint, for sure.
I really like this! Nice rendering in particular! As far as critique, I think his left ear (picture
