Here's why:
* Super Sonic is not a playable form in Sonic Unleashed. The game focuses on Sonic's Werehog transformation and his standard Sonic form. While there are power-ups and special abilities, Super Sonic is not one of them.
* The game's story revolves around defeating Dark Gaia and restoring the world. Super Sonic's role is not necessary for the narrative or gameplay.
Although you can't become Super Sonic in Unleashed, you can experience the game's different forms and enjoy the unique gameplay mechanics offered by both Sonic and the Werehog.