Jazza sent me here;) I think this is amazing, I would eat a brick for this kind of talent. Yes, a brick.

On its way to being a very impressive piece of work! I feel like you might have suffered from a common scourge to drawing in pencil, and that is the nasty smudging that happend as you slide your hand over the paper in parts you've already drawn. Here's a tip I used to always keep in mind when shading in pencil, I'd rip up a portion of a separate piece of paper and put it under the hand that's drawing. That way you can slide your hand around without exposing your drawing to all the oils our hands naturally hold. Another thing I think this image could use, is a litte definition through light and shade. Minimizing the smudging like I mentioned will help keep the light in tact, but when you approach the dark parts of the shading, make sure your pencil is extra sharp, and you're not afraid to be firm with it. You'll end up with a really strong contrast and it'll make your sketches 'pop'! Overall, you've done a great job here! Keep it up :) (gotta love blizzards art style. I'm definitely a fan myself)