Code 03002AF005 will allow you to access a basic debug menu where you can warp to any point in the game, listen to all of the music and sounds in the game. There is also an unused screen. ROM text for the debug menu can be found starting at 0x2F544.
STAGENO will allow you to start at any stage in the game.
The sound test allows you to listen to any song or sound effect in the game.
Allows you to select any area in the game.
An unused screen listed as CSOON, a leftover from a demo or sample version.