Press Up, Down, Down, Left, Right, [Space] at the title screen. Note:
Only a single level may be completed with this feature enabled.
Development team high scores:
Press Right, Right, Up, Up, Down, [Space] at the title screen.
Press Down, Down, Down, Left, Right, [Space] at the title screen to
enable the sound test screen and chat mode. Enter and play one of the
corresponding sound combinations to activate the corresponding cheat
Debug mode PCM12, DA11
Bonus levels PCM07, DA07
Display artwork PCM03, DA01
Human-faced Sonic PCM12, DA25
Hercules Sonic PCM04, DA21
"Revenge of the Mutant Artwork" PCM11, DA09