Very outstanding drawing. The first reaction when I saw this drawing was like "oh my god, how is this possible?" But then I took a 'deeper' look into it and found a few little mistakes. First one is lighting. Maybe I'm blind or something, but in my opinion it's not looking very logic. As I can see the lighting comes from the right side, all those highlights are looking really good, but if you really want it to look more realistic - try darkening the left side of the head a bit more. Second one is fading out shape or something like that. I don't really like how the drawing ends up, I would like it more if it fades out somehow. But those mistakes are hardly noticable. Nevertheless I really love the drawing, sorry if my critique sounds rude, cause English is not my native language so I still can't write clearly, exactly what I think. I just couldn't miss a chance to write a critique on this drawing. Remember, that was just my opinion, so you can ignore it. Keep it up, and good luck. P.S. Let me know if I spelled something wrong.