Ditto on the snout. He's also a little lanky looking for Sonic. However, you really did a great job animating the spines. Thumbs up on that bit.

Maybe you could have the two arms move differently instead of in perfect unison? It would look a bit more natural if the arm and fist closest to the viewer moved a bit more than the arm and fist on Sonic's opposite side. He looks a bit bow-legged too, but I don't have any suggestions on how to fix that right now.