At the title screen, where it says "Push Run Button", press the following buttons.

Code	Effect
I, II, I, II, Run	Sound Test.
I, II, Up, Down, Left, Right, I, Run	Change Ship Type.
Up, Left, Down, Right, II, I, I, I, Run	Invincibility.
Up, Up, Down, Down, Left, Right, Left, RIght, II, I, II, I, Run	Shooting Mode.