Wow! He certainly looks menacing.

The idea is great, but you could improve on the shading. Nice job though.

Yeah I'm not to fond of the outcome myself. I started over with a new fresh shroom (it can be seen in the W.I.P. part of the forum. Hope it'll turn out better than this one. Thanks for the comments though

It isnt too bad, but it could definatly be better. In addition to whats already been mentioned, I think more contrast between colors would improve it a lot. And remember: the lightsource isn't the only thing that influences the shading, the shape does too.

Also, the blood on the teeth looks sloppy, maybe make it with less colors. 

then you have to fix that pillowshading up there.

The dithering is not really working.
It's making it look worse, in my honest opinion.:S