It's a bit hard to see the butterfly shadow... not sure how you could bring more attention to it (if I didn't know it was a shadow contest I probably would have missed it).
Not sure which direction you could take to improve the image to give the shadow a little more punch. But that's just me. It's a very enchanting image in it's own right
Good luck.

I love the idea and his shadow/wish is actually an attainable goal for him, so that's a nice 'looking to the future' concept. Maybe make it daytime or sunrise/sunset so the shadow is more noticeable.

I think the shadow would be more noticeable, if you use another pic of the moon where the clouds were not so dark. Your image is nice, but work on the shadow.

I like the idea of caterpillar > butterfly shadow but I would have put the shadow over the moon since that is the focal point in your image (kind of a Batman silhouette). It took me some time to find the tiny shadow on the tree.