Successfully complete story mode to unlock more playable characters.
Play as Big The Cat
Purchase all pictures of Tails in Sonic's room to unlock Big The Cat in versus mode.
Play as Chao
Purchase all pictures of Knuckles in Sonic's room to unlock Chao in versus mode.
Play as E-102 Gamma
Purchase the last picture of Amy in Sonic's room to unlock E-102 Gamma in versus mode.
Play as Super Sonic
Purchase all pictures of Sonic in Sonic's room to unlock Super Sonic in versus mode.
Successfully complete the game and enter Sonic's room to find the Notebook on the table.
Set the Dreamcast system date to December 24 to replace Lumina with NiGHTS. Note: All characters may need to be unlocked first.
Place the game disc in a PC compatible CD-ROM drive to find artwork from the game in the "Sonic Shuffle" folder.