Bonus rounds (Classic version):
To unlock bonus rounds in the Classic version, at the title screen, press L, R, L, R, L, R, Right, Select. Touch the door that will now appear in level 20 to start the bonus rounds.
Shoe power-up mode (Classic version):
To unlock Shoe power-up mode in the Classic version, at the title screen, press Select, R, L, Left, Right, R, Select, Right.
Super Bubble Bobble (Classic version):
To unlock Super Bubble Bobble, defeat the Classic version Boss with two players. Then, at the title screen, press Left, R, Left, Select, Left, L, Left, Select.
Hidden Coke can item (Classic version):
To unlock a Coke can that when collected triggers a meteor shower that kills your enemies, enter “I.F” as your initials at the high score screen. The Coke can will appear on Floor 1.
Levels 91 to 100 (New version):
To unlock the final ten levels 91-100, collect all nine letters from all nine bosses throughout the game. You must kill four enemies with one Super Bubble and collect the key they drop. After you defeat the Boss of that group of levels, it will drop a letter instead of the big gem.
Play as Robolun (New version):
To play as Robolun, beat all 100 New version levels.
Play as Lovelun (New version):
To unlock Lovelun, beat all 100 New version levels.
Continue game play (Classic version):
In order to continue from where you left off after dying in the Classic version, after you receive the “Game Over” screen, go back to the screen where you start on level 1 and scroll down. You will see the Bubble Bobble dinosaur go down on a elevator platform to stop at the last level you were at.