Its a good idea (we need an icon like this), but the shadows on the face do not work. In fact, the face's proportions are kind of bizarre. The eyes should be higher up in relation to the chin, and a nose might be nice. Also, try to think about where the light is coming from while you do your shading. There is no logical explanation for a big shadow across the middle of the face, especially given the lack of said shadow on the tunic. The neck, however is well shaded with a head above it (head blocks light). The tunic is also fine. One last thing: why is he so angry? - Only joking.
In short:
Keep the neck and tunic
Move the eyes up
Add a nose
Lose the shadow on the face
Add better shading