Link mode
Hold down [Select] and press [Up], [Down], [Left], [Right], [Down], [Up] at the options menu . The "Players 1 or 2" option will be unlocked, which allows the two player mode to be played on two Game Boy Color systems using a link cable.
Play as Tiny
Select Ralph as a character, then intentionally die. Then, quickly press "Select, A, B"(2), "Up, Down, Forward, Back" after transforming into a person.
Glitch: Float in mid-air
Hit a neon sign just as the building that your monster is standing on begins to collapse. If the building falls down while your monster is still being shocked, it will remain in mid-air.