The animation is indeed fantastic, very smooth and tireless to look at.
I didn't realize it at first but I totally notice Hapiel's point now. Maybe you could edit it some time later and "spot" the head, that would take this piece flawless! 
A graceful dip and rise in vertical motion, a convincing pirouette in horizontal motion, an interesting smear on her left arm in the last frame or two, convincing shadows on the legs and unobtrustive lighting on the rest of the body. I hate animating so I always have respect for animators, and this is a very nice piece.
Well done, this looks great!
As for the motion though, normally a dancer would 'spot', and keep their head still for as long as possible!
thank you! that's right, forgot to spot. will fix it next time!