right before you fight the last boss in the last level great maze, sonic appears.when he joins your team and you quit adventure mode, you'll unlock him for good.
The Adventure mode of Super Smash Flash 2 is likely to only appear when the full game is released.
mewtwo is a
You unlock him when you are playing Adventure mode. He is at the very end.
Sonic Underground is an animated TV series. And no, you cannot unlock episodes, or characters other than Sonic, from Sonic Underground in Super Smash Bros Brawl.
If you're thinking of the Sonic Riders character, you cannot unlock him in Brawl.
By completing SSE (Subspace Emissary or Adventure Mode.)
no, however you can unlock him in super smash bros. brawl
Unlock Sonic
u unlock sonic to get his stage
"Clear Classic Mode with 10 Characters or 300 matches. Sonic is also known to appear randomly after clearing a few brawls, just try playing the subspace emissary and clear the stage.""http://hubpages.com/hub/how-to-unlock-brawl-characters--how-to-unlock-super-smash-bros-brawl-characters--unlock-brawl-characters--wii"
Unlock sonic in the subspace emissary and you will get shadow the assist trophy.
you can get it as a assisted trophy after you unlock sonic in super smash bros brawl after play 300 matches, beat classic with 10 character or have sonic join after you beat sse
Sonic is not a playable character in Super Smash Bros. Melee; only in Brawl. Therefore, he cannot be unlocked in Melee.
complete adventure mode with s.sonic