Contrary to common belief, Flying Battery is not featured. Act 1 is largely based on Lava Reef Zone.
Act 1 also takes level design cues from Hydrocity Zone. * This zone is mostly based on the following act, Ocean Palace. Sonic Adventure 2: City Escape, Final Rush * The setting for the Rival Boss Fight against Shadow.* The setting for the fight against Perfect Chaos ( Sonic Adventure's Final Boss). Sonic Adventure: Speed Highway, Station Square.Sonic 3 & Knuckles: Sky Sanctuary Zone * Which also takes design cues from Marble Garden and includes an interior section reminiscent of the Hidden Palace.* The setting for the Rival Boss Fight against Metal Sonic. Sonic CD: Stardust Speedway (Bad Future).Sonic 2: Chemical Plant Zone, Death Egg Zone, * The setting for the fight against the Death Egg Robot (Sonic 2's final boss).