While some of the sprites are okay, the character seems unfinished. There's a lack of polish for the running sprites, back sprites, etc, I can see blatant edits of the original sprites which makes this resemble Gamebanana addons.
What really proves this needed more time before public release is the fact that you get no real reward when you collect the chaos emeralds. You are not allowed to turn super, and even if you were to, there'd be a lack of proper sprites.
I can see the potential of this, but as I said this really needs more polish and time for it to be considered really good.