really good layering. Are you planning on doing anything else with it? I bet you could lay some really nice colours down and create a really moody ambiance. This is going to sound weird, but I really like the windows in the back, too. Visually it all creates a really good lead right to the focal points.
You're pretty good in life drawing. The only thing that I think it seems off is the thumb of his left hand, it looks oddly curved, but the rest is pretty awesome.