At the title screen, select Options. Highlight Sound Test then play the following music and sounds: 19, 65, 09 and 17. You will hear a ring-collecting sound for correct code entry. Then press START to return to the title screen. Highlight 1-Player, hold the A Button (defaults to the Y button on 3DS) and press START. You are directed to Level Select Screen. Choose a level then press START to begin.

Code	Effect
17	Play Invicibility Music.
65	Plays a Shifting Sound.
09	Plays Casino Night Zone 1-Player Music.
19	Plays Sonic 2 Theme.