i really like the shader in this. but it should fit to the other part. on the other side..
i will show some critic on your flat.
good thing is also the mapping ^^
you should maybe try to use not that much different things in this head... i like the mouth. but i think the back of it should be darker. the teeth are cool. not dublicated and nothing. the same on the brain thing but maybe make it look like a brain or somethng these spirals dont look that good in this part.
you showed us you have the skills for a good head but but dont use
them all in one. :P
P.S.: sorry for my bad english ^^