Whoa. o_o ::hides:: He's scary!
Hmm ... interesting choice for the hair. I do have to say, though, that the lighting in the picture doesn't seem to make much sense ...
The way it looks, you have light coming from above on the hair, yet light coming from below/sides on the cheeks and ears ... while the T shape of the face is flat and unshaded. It may help to create a more interesting picture (not to say that yours isn't already interesting) if you study the face in lighting situation, and put a little bit more detail into the shading.
It also looks somewhat like the expression was pasted onto his face, rather than it being a result of the muscles beneath the skin moving. There should be some tenseness visible, especially around the brow and upper lip.