I edited the hammer shading a little but now it doesn't go with the rest of picture, looks different..
Wanted to post it anyway. xD
I think what's happening in yours is that the second light source lighting the top of the shadow that you added should probably also at least moderately light up that dark shadow on his leg and arm. It being as light as it is (the snow he's standing on is a straight up RGBx255), you can't realistically expect a black, black shadow like that. I'll have to try to rework it to include some more light hitting that side. The original drawing never took a background in to account:
Yeah, it was drawn on a post-it at work with a ball-point. I recently got my scanner working on my Linux box, so I figured I'd scan this in, which is the genesis of this thing. I read Arne say somewhere on this board that that was how he started his pixel work (at least, I think I read that, might have been someone else), so I gave it a try.