Also, I feel as if the fire is not very noticeable, and perhaps should just be fire all the time instead of a little circle. And the skulls are alright when they're flying by, but when they're just sitting there, I feel they're a little misplaced... and overkill.
I really liked this game. For a sequel, though, I'd do Bunny Ears instead of Fox Ears. Also, I'd focus on making the Fox, Wolves, and Bears having looks that differ from one another more significantly. Up until I got the fox ears, I thought the gray wolves were gray foxes :P And when I was focusing on jumping, I thought the bear was a fox. I'd also perhaps make the colors a bit brighter? Not cheery bright, but I feel everything blends in, like the toadstools and the graves, and they're easy to miss. Perhaps more badges too? But, either way, I'd definitely play a sequel to this. :)