A really cool way to shade him, and I like his face, the top of his head, and the back, personally I think on the left and right side, there would be darker shading in the middle, where his cheekbones would be. When I think of slenderman, I think of, well a slender tall dude with no face. So to me it would make sense that his cheekbones would be pronounced. But this isn't just criticism, it's really very nice, I'm just giving a lil advice :P Really nice job on the shading though. I always loved the extreme shaded skins.