Bubble Bobble
# A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
Debug mode
At the title screen, press Down, Up, Down, Up, Right, Down, Left, Down, Up, Down.
Level skip
Enter debug mode. Then while playing a game, press L1 to skip to the previous level or press R1 to skip to the next level.
Debug menu
Enter debug mode. Then while playing a game, press R2 to display the debug menu, and press R1 to hide the debug menu. This displays the map number, Bub's lives, and Bob's lives.
Original version
At the title screen, press Right, Left, Up, Down, Up, Down, Up. Now the original version of the game allows you to enter the diamond rooms at levels 20, 30 and 40 even if you lose a life.
Alternate bonus effects
Enter one of the following initials on the high score screen, then start another game. The new effects will appear when certain bonuses are collected during the game: