the image is too dark, would make a lovely manipulation otherwise

I also would have blended the bottom of the mushrooms with the ground more like putting some grass in front of it. Or actually since the mushrooms look a bit cartoony, I would have just made the whole thing look more cartoony with the Poster Edges filter. But that is just my opinion. I do like the colors of the mushrooms though.

The background is too dark. It makes the mushrooms look like they are floating in the darkness, rather than being in shadow. I'd suggest bringing up the ambient light a bit.

i like this...