the hell gate needs something filling in the blank spaces, even just a texture
the skull at the top could use some depth, too
and the character looks great, tho the face has little readability
her animation might move a bit too much for just breathing
having it run down the entirety of the legs might be a bit much
also are the bits of her hair supposed to stick out?
overall this is great stuff, cant wait to see how this all ends up =]