Press Down(3), Left, Right, A at the title screen while "Press Start" is blinking to display the sound test menu. Set one of the following sound combinations and press Start to enable the corresponding cheat function.

Sounds Effect
FM07, PCM07, DA07 Special levels
FM42, PCM03, DA01 View hidden scene
FM46, PCM12, DA25 View hidden scene
FM42, PCM04, DA21 View hidden scene
FM40, PCM12, DA11 View hidden scene
FM44, PCM11, DA09 View hidden scene