Beat the Hero storyline to unlock Babylon storyline, Mission mode, and buying skates at the shop.
Beat the Hero storyline to unlock Shadow The Hedgehog, Rouge The Bat, and Cream The Rabbit.
Beat the Babylon storyline to unlock Eggman.
Beat Storm's, Wave's, and Jet's missions to unlock AiAi, Ulala, and NiGHTS.
Accumulate 15 hours of gameplay to unlock E-10000G
Accumulate 50 hours of gameplay to unlock E-10000R
Play as Super Sonic:
First, you must get all the gold emblems in mission mode. After that, a chaos emerald will be selectable as one of Sonic's extreme gears. Select it, and Super Sonic will appear.
Beat the Hero storyline to unlock Shadow's Darkness jet shoes, Rouge's Temptation board, and Cream's Smile board.
Beat the Babylon storyline to unlock Sonic's Blue Star II board, Eggman's Egg-Rider scooter, and the Magic Carpet.
Beat Storm's, Wave's, and Jet's missions to unlock the Hang-On gear, Opa Opa gear, Super Hang-On gear, and The Crazy gear.
Win the Heroes Cup with a Gold Emblem to unlock the Sega Carnival track, and win the Babylon Cup with a Gold Emblem to unlock the Sega Illusion track.
Thanks to Revolution Reader Camma, Bradlee, Sho-gun, and bigallen!