The game is supposed to have some focus on drifting (but Tails flies and Ulala floats!)
Here is a তালিকা of confirmed playable characters. I dont know if the তালিকা is complete, I pasted it from somewhere.
From Sonic the Hedgehog:
* Sonic the Hedgehog] * Miles "Tails" Prower * Knuckles the Echidna * Doctor Eggman * Amy Rose * Shadow the Hedgehog * Big the Cat
From other Sega properties:
* AiAi from Super Monkey Ball * Amigo from Samba de Amigo * Ryo Hazuki from Shenmue(the character from my user icon) * Beat from Jet Set Radio * Alex Kidd from the Alex Kidd series * Billy Hatcher from Billy Hatcher and the Giant Egg * Zobio and Zobiko, the zombie couple from The House of the Dead EX * Ulala from মহাকাশ Channel 5 * B.D. Joe from Crazy Taxi * Jacky Bryant from the Virtua Fighter series * Bonanza Bros. * ChuChu Rocket * Opa-Opa from ফ্যান্টাসি Zone