Cheat mode:
Press 1, 1, 9, 3 at the title screen to enable cheat mode. Then, press one of the following buttons on controller two while playing the game to enable that particular cheat code.

Faster foreground scrolling = A
Slower foreground scrolling = B
Unlimited special weapons ammo = C
Power-up gun = 1
All bomb power-ups = 2
Flag other moons completed = 3
Invincibility = 4
Select sounds = 0
Play selected sound = *
Slower background scrolling = Left
Faster background scrolling = Right
Skip to next stage = Option