Instant Level Clear
This is a pretty tough puzzler, but with this code, you can win any stage! Start a stage, then press Start to pause. When you have done this, press and HOLD Select, and press Start again, unpausing. Hold BOTH buttons down as you unpause, and keep them held for about five seconds. You should see the level clear screen spring up. This is not an easy code to pull off, but it's worth it.
Password To Level 99
At the password screen type in R61H and you'll be at level 99.
Complete Current Level
At any time during gameplay, hold Start, then press Select, then release all buttons. Unpause the game and wait a few moments for the "Level Complete" message to appear.
Level Select
At the title screen, hold Down+A+B, and press Start. Press A or B to select a new level.
Music Test
Press and hold Down + Left + A + B + Select before the title screen appears, and you will have a new music test option when pausing the game.