Caterpillar - Finished

Does this look better with the grass or without it? [link]

This is a piece for a book character competition [link] by :S It's the caterpillar from Alice in Wonderland, fused in with the one from A Bug's Life. The Mushroom was traced - from here [link] but the caterpillar and the bong were hand drawn. It was done using Adobe Illustrator, with the gradient mesh tool and the gradient tool.

The tutes used were: [link] for bubbles and [link] for general blending. There is also [link] for the brushes of the grass.

If I could have thoughts about the lighting and shadows, their direction and the colour scheme I've got. That would be much appreciated. I would also like thoughts on the thickness of the stroke - should it be thicker? Also, is the composition of this piece too crowded - does it distract the viewer from the caterpillar? My brother and sister were also concerned that children should see this - should it be rated M? I don't think so - kids wouldn't understand it but others might feel different.