This is very well drawn, and completely original. The work may look slightly sloppy but hey, its not that bad! This work is truly art and is wonderful... I love the background a lot...

Anyways, its good already but you could improve this by making a more sharp outline, adding texture ad cleaning it up a bit... Maybe a little more shading...

Basically overall the only thing really problematic about this drawing is those uncolored spots...

Well umm... all that's left. this is truly a great drawing though it might need some work... but really, is a drawing ever finished?