The first thing that strikes me in comparison to the
sketch, is that the skin color variation has been reduced-
was this intentional? A variation of skin types (specularity/color)
very much helps to sell the end image- you might
experiment a little bit by exaggerating it in areas.
Beautiful work though, I like it very much!
Throw in some gangly hair, dirty nails and
some open cuts!
A material change between the skin, nails and
horns would add a lot too
great work again!