In Normal Mode, beat the boss of level 70 without getting the 7 potions.
Bad Ending 2
In Normal Mode, get the 7 potions, then proceed to level 80 and beat the last boss.
Bad Ending 3
In Super Mode, beat the boss of level 70 without getting the 7 potions.
Good Ending
In Super Mode, get the 7 potions, then proceed to level 80 and beat the real last boss.
Power Up
up, right, left, down, up, right, left, down. Doing two clockwise cirles causes Bub and bob to have permanent shoes, blue gum, and yellow gum.
Practice Ending
Beat the Practice Mode.
Super Game
Left, Start, Bubble, jump, up, down, start, right. You get the second set of levels when this code is used. It does nothing special on a machine with Extra Mode enabled. I recommend avoiding this code until you have beaten the game in normal mode, so you don't miss part of the story (and the fun!).
Bad Ending 1...