i love this, and i love that the only color you have used is to accentuate her eyes - which are a voluptuous red. making them very sensual, but also demonic.
i'd say the curve of the waist cuts in a little too much, but it may just be the angle that she stands. sadly i am not great at anatomy.
i love that the skulls add all of the shadow to the picture, but do not take the focus.
you have a very strong piece of art here. something I would happily display in my hallway.