Bonus rounds in Classic version:
At the title screen in the Classic version, press L, R, L, R, L, R, Right, Select. Touch the door that now appears in level 20 to start the bonus rounds.
Shoe power-up mode in Classic version:
At the title screen in the Classic version, press Select, R, L, Left, Right, R, Select, Right.
Super Bubble Bobble in Classic version:
Defeat the Classic version Boss using two players. Then, press Left, R, Left, Select, Left, L, Left, Select at the title screen in the Classic version.
Levels 91 to 100 in New version:
Collect nine letters throughout the game. You must kill at least four enemies with a single Super Bubble, then collect the key that they drop. After defeating the Boss of that group of levels, it will drop a letter instead of the big gem. You must collect a letter from every Boss in the game (nine total) to unlock the final ten levels.
Play as Robolun in New version:
Successfully complete all 100 New version levels to unlock Robolun.
Play as Lovelun in New version:
Successfully complete all 100 New version levels with Robolun to unlock Lovelun.
