You seem to use the "Over - sized Head" Sonic a lot when in your animations. Not saying I have anything against that - And I would recommend leaning him forward a bit. He seems to up - right, if you know what I mean. Here is the classic animation - How he has a bent back.
AND MAKE HIM ANNNGGRRY. HE'S RUNNING SO HARD ONLY TO KICK ROBOTNIK'S FAT ASS. ARRGGGH.