Press one of the following keys during game play. 
You're inside the game, press numbers 1 to 8 for following:

Key   Effect
------------
[1] - "Dual color bonus"; Can be used as a bubble of either color.
[2] - "Double score bonus".
[3] - "Prompt bonus"; Shows trajectory of ball.
[4] - "Layer up bonus"; Returns offending bubbles few layers up.
[5] - "Freeze bonus"; Freezes all bubbles in the cave.
[6] - "Triple score bonus".
[7] - "Bomb bonus"; Blows up all bubbles around itself.
[8] - "Repaint bonus"; Repaints black bubbles into one of the existing 
       colors in the cave.