BUBBLE BOBBLE
-------------
 
If you can get to boards 10, 20, 30 & 40 without dying a door will
appear to take you to a secret level. On boards 7 & 22 wait a few seconds 
until the umbrella falls and grab it, you will warp ahead 6 levels.

CHEAT MODE:

 In some early versions of the game only, simply press:

 [F1] - To advance 01 level.
 [F2] - To advance 06 levels.
 [F3] - To advance 11 levels.