Ooh, one of your best!
It's interesting to do zombie pics of actual people. I believe there was something else called "Hollywood Zombies", but this actually seems better than that. What really works is that you get the splashes of blood flying everywhere just right. The way his nose is ripped off makes him look like a pig. He seriously doesn't even look like a black man in this, he looks like the skin color of any zombie. I like how there are different tears in his face.
The blood is also black (or at least dark red) near the places around his mouth. It's stuff like that that puts depth in your work. The colors make it seemed like this was drawn on scrap paper or something. Well, it certainly is a change from what we in America previously had for Presidents. The creases make it seem more authentic, too.