It's nice. However maybe you should have the linework thinner and smoother on some parts, like the hand for example, its a little rough, and would probably look better if the lines were thinner in that part of the picture. Either that or find some way to help them make a better transition to the rest of the picture, maybe some sort of texture that helps them blend to the rest, while not making the picture blurry..
If you aren't already using it. I suggest using Paint.net for linework if you are having trouble making smooth lines with no squiggly marks. It actually beats Photoshop for linework for those who do not have a tablet.
With a few fix-ups, this would be a very cool drawing, otherwise, its nice as it is.