Great software SAI, first off I love the dramatic chiaroscuro effects of the lighting, the brush strokes at the bottom is a great touch and looseness to the more refined and detailed upper portion of the piece. The monochromatic color scheme of red is very pleasing and brings out an emotional feel to the piece, really like the eyes and the highlights. No real proportional flaws except maybe the placement of the eye to the right may be to far to the right and the nose may be a bit smaller than it should be but not real noticeable.
Overall this is done very well, I can see it used a movie poster of some sorts...