Secrets

Enter these cheat codes at the Password screen
Password ... Effect
!CR3D1TS! .. Enable Credits Music in Sound Test
!SH0WT1M3! . Enable Master Cheat (Level Select)
!W1LDL1F3! . Enable Master Cheat + Invincible
!G4X! ...... Enter Music Jukebox
!3ND0FD4YS! Show End Part
!G4LL3RY! .. Show Gallery
!4BYSS! .... Show Secret Gallery