Highlight the "Level" selection on the setup screen. Press Left(2), Right(2), Down, Up, Down, Up, A, X. The "Crazy Hard" selection will appear.
Level Select
Press A(3), B, Y, R, Select, L, Down, Up, Down, Right. The copyright and licensing screen will appear with the level number.
Raise Score to desired point by defeating infinite enemies
In the first level inside the ship, proceed until you're past the wooden crate walls, which you broke through with your rocket. When ricocheting off walls toward the end of the level (before the boss), there should be a space inside the wall on the right. Jump in and walk in. If you're in the right place, you should find some sort of wooden wall built into the stage wall. Charge into it to break it, and an explosion will show up. Infinite enemies will spawn from the explosions. Maintain a distance from them, face the explosion, and press the attack button repeatedly to kill enemies the second the spawn. Kill enemies until desired score is reached.
Sound Test
Highlight the "Sound" selection on the setup screen. Press Select to stop the current song. Press various buttons to play different sounds.
Various Passwords
At the title screen select password and attack the empty boxes to change them.
A: Apple B: Banana C: Crystal N: Nothing
T: Top row M: Middle row B: Bottom row
Crazy Hard Difficulty...