I second the bouncing actually looking good.
But some quick, messy edits:
I guess I don't really understand why you're shading the left side the same color as the front. You might have to change around the anatomy a bit, but you should think about where exactly the wheels, arm, and ears should be relative to the body of the guy. For example, you had an outline in front of the right ear, but not the left. Why? Aren't both ears on the front of the box? If they're on the sides instead, pointing opposite directions, you shouldn't be able to see the inside of the right ear, and the left ear should be along the slant instead of along the flat top. Just things to consider. Also, your shading seems a bit arbitrary, like the highlight on the tail and the shadows on the arms. Where is the light source?