Poor guy has an arm stuck in his head. I have to say this is I think a first I have seen u use grunge brushes. I am not sure how effective it seems its almost liek an afterthought. But my immediate reflection after seeing this is the ghouls in Fallout 2. If you have never played that game and like RPG I highly reccomend it.
Damn. That's quite a fine zombie you've done there.
The character himself is awesome. His form is superb. Starting from the face, the bags under the eyes, the lack of nose, the apparition that he's in urgent need of some dental work, combined with the shape of the head and the wispy hair makes him look mighty creepy. The forearm through the ear is a wonderful addition.
The body work is amazing, how you've made him so skinny with his skin stuck to the bones works brilliantly, especially with the ribs and his stomach. The linework, as with all of your work, is so simple yet so damn effective. The pants are a great addition, nice shading work there, and love the addition of a cord as a belt
I must commend you on that hand. The shape of it looks great, especially around the thumb and the finger on the far left. Also the way you've given it that boney, scrawly feel works great.
The one thing I don't like is the grungy brushes. I know that it fits the whole scene, but I think it detracts a little. Although it does work in taking the focus away from the background somewhat, so that's good.
Nice piece overall, love the fact at how great your doodles can look