The dithering on his face makes it look as if the light source is the atari.  Is this the case?  If so, the shading on his arms should be reversed.  Maybe the atari should be lighter as well, if it is the beacon of light? :)

With his hair and his shadow however, the light source is above him.  Are there two points of light?  Perhaps you could put the light source behind him.  I think the problem for me is too many lights sources. Start with one, it's easier, I promise!

Clothing I am not good enough at really to comment on in depth but from what I see you could perhaps use another tone to define depth, the fabric lacks volume at the moment.

I like the character though and the sentiment ;)