The "Plus" expansion adds , the ability to play as Amy Rose in the core Genesis games, and Knuckles as a playable character in Sonic CD .
the game involves unlocking the classic level select and debug menus, which function similarly to the original Sega Genesis versions. Steam Community Level Select Code (Title Screen) Debug Mode (Sound Test) Up, Down, Left, Right (Hear Jingle) 01, 09, 09, 02, 01, 01, 02, 04 Up, Up, Up, Down, Down, Down, Left, Right, Left, Right 01, 09, 09, 02, 01, 01, 02, 04 Sonic 3 & K Up, Up, Down, Down, Up, Up, Up, Up 01, 09, 09, 04, 01, 00, 01, 08 3. Content Added in "Plus" sonic origins plus rom