Title screen says Sonic 3 (duh)
Data Select uses old Sonic 3 format. This slot says clear, but I'm only up to Mushroom Hill
Level Select is from S3K, however the following levels are unavailable: Lava Reef 3 and 4, The Doomsday 1 and 2, Bonus 1 and 2, and Special Stage 1 and 2. All of these can be accessed with the debug code:
Play 01, 03, 05, 07 and debug is now active.