Is this called vectoring a picture? I tried it for first time below... I followed a bit of a tut and you basically do lots of shaped layers building the colours u, and it takes ages probably wouldnt do it again then once i had done that i cleaned it up abit.
Looks really cool man. Just the part above the sun glasses on the forehead, that is a really light shade of tan seems too light. Other than that it looks really cool.
Instead of using black for the background use a color and i think its a bit to much stuff, kills the focal.