Unlock Boss Attack Mode
     Complete  either Hero or Dark side story modes. You'll be able to
fight each boss from either Hero or Dark side.

Unlock Chao Dark Garden
     Raise  a  Dark  Chao  with  one  of  the  three  Dark characters.
Continually  feed  and train your Dark Chao and it should evolve. Once
it  evolves, descending stairs will appear at the main Chao lobby that
lead to the Dark Garden.

Unlock Chao Hero Garden
     You must raise a Hero Chao with one of the three Hero characters.
Continually  feed  and train your Hero Chao and it should evolve. Once
it  evolves,  ascending stairs will appear at the main Chao lobby that
lead to the Hero Garden.

Unlock Green Hill Stage
     To  unlock  a  3D version of the Green Hill stage (from Sonic the
Hedgehog  on  the  Sega  Genesis), earn all 180 emblems. The new stage
will appear on the world map.

Unlock Kart Racing game
     In  the  Hero Side story, complete the Tails driving quest and in
Dark Side story, successfully finish the Rouge chase mission.

Unlock Last Stage
     Finish  both  Hero  and Dark side story games. Once done, go into
story  mode  and  a "Last Stage?" menu selection should appear between
Hero and Dark selections.

Unlock Super Sonic and Hyper Shadow
     Complete "Last Stage?" in story mode.