Enable the "Sound test" code. Press Select, Up, Up, Down, Down, Left, Right, Left, Right, II, I at the sound test menu.
Final Boss battle
Hold Down + I and press Run at the "Input your birthday" screen.
Mini-game
Enable the "Adjust brightness" code. Press Select until a flashing red screen appears. Then, press II, Up, Up, Down, Down, Left, Right, Left, Right, II, I. Use the D-pad to move, II to shoot, and I to fire a smart bomb during the mini-game.
Mini-game
Enable the "Adjust brightness" code. Press Select until a flashing red screen appears. Then, press II, Up, Up, Down, Down, Left, Right, Left, Right, II, I. Use the D-pad to move, II to shoot, and I to fire a smart bomb during the mini-game.
Monochrome mode
Press Select fifteen times in level one during game play. Press Run to pause game play, then hold I and press Up.
Sound test
Hold Up + I and press Run at the "Input you birthday" screen to display the sound test menu. Note: The duration that Run must be pressed is very precise.
Unlimited extra lives
Pause and resume game play one hundred times. All enemies that are shot will turn into bonus lives.