In addition to being able to play the lock-on versions of "Sonic the Hedgehog 3" and "Sonic & Knuckles", new gameplay features were added to the game that were not previously available.
- Knuckles can be played in the "Sonic the Hedgehog 3" Zones; however, the opening cutscene from "Sonic & Knuckles" has been removed.
- Tails can be played in the "Sonic & Knuckles" Zones (except for The Doomsday Zone).
- Passing a Star Post can open up three bonus stages: the Slot Machine Stage (twenty-thirty four Rings required) and the Glowing Sphere Stage (thirty five-forty nine Rings required) from "Sonic & Knuckles," and the Gumball Machine Stage (fifty-sixty five Rings required) from "Sonic the Hedgehog 3."
- The save feature from "Sonic the Hedgehog 3" allows game progress to be saved in all Zones in the game.