I completely love this photo. The composition is awesome - bizarre, claustrophobic, more than a little disturbing but with a subtle hint of comedy. The model's make-up lifts this from a darker place and gives it a more theatrical feeling, enhanced further by the mime-like clothing.
The little bits of tension running through the image give it a more challenging edge. From the almost suspicious look in the model's eyes to the uncomfortable-looking bends in her fingers pressed against the wall of her prison, there is more than a hint of carefully calculated discomfort.
I don't have any suggestions to make for this. I stared at it for absolutely ages and was going to leave a comment but when I scrolled down and noticed that you had critique enabled I figured I ought to make use of that function even though all my thoughts on this picture are positive ones.