Here are some cheats and tips for the game Bubble Bobble DS.
Classic version: Bonus rounds:
Press “L, R, L, R, L, R, Right, Select” at the title screen in the
Classic version. Touch the door that now appears in level 20 to start
the bonus rounds.
Classic version: Shoe power-up mode:
Press “Select, R, L, Left, Right, R, Select, Right” at the title screen
in the Classic version.
Classic version: Super Bubble Bobble:
Defeat the Classic version Boss using two players. Then, press
“Left, R, Left, Select, Left, L, Left, Select” in the Classic version.