Super Sonic is not a playable character in Sonic Colors. The game only features Sonic and Tails as playable characters.
However, you can find a special Super Sonic themed stage in the game:
* The "Super Sonic Blast" stage: This is a special stage accessible after completing all the levels in the game and collecting all the Red Star Rings. This stage lets you play as Sonic while wearing a Super Sonic costume, but you don't actually have the Super Sonic abilities.
So, while you can't unlock Super Sonic as a playable character, you can experience a Super Sonic themed stage in the game!