I would have to have that in terms of Anatomy and the deformation of the body is great, you could improve the lighting of the scene.
Because this drawing looks very flat. if you added more light to one side and added a casted shadow it would improve the overall quality of the artwork.
One quick advice from me is to add a Back light. Use this picture as reference.
http://digital-photography-school.com/wp-content/uploads/2007/05/back-light.jpg
But from my experience when doing figures, having the back light to one side creates huge amounts of contrast that draws the viewer in.
I hope this helps you. :)