How do you unlock super goku on dbz sonic warriors 2?

You can't unlock Super Goku in DBZ Sonic Warriors 2. The game does not feature a Super Saiyan Goku, nor does it have any kind of unlockable characters.

The roster in DBZ Sonic Warriors 2 is fixed, and it includes the following characters:

* Goku

* Vegeta

* Gohan

* Trunks

* Piccolo

* Freeza

* Cell

* Majin Buu

While the game features a lot of cool moves and transformations for the characters, Super Saiyan transformations are not included.