To enter these codes you must first type GUBBLEDCHEAT at the title screen. You'll hear Gubble D. Gleep laugh, letting you know you've entered the code correctly. Now press the following keys below:
F8: God mode toggle. *only works during play*
F9: Complete any level. *only works during play*
+: Speeds you up. *only works during play*
-: Slows you down. *only works during play*
Page Up: Warps you to the next level. *only works from a launch pad on the map*
Page Down: Returns you to the previous level. *only works from a launch pad on the map*
Home: Advances you 10 levels. *only works from a launch pad on the map*
End: Takes you back 10 levels. *only works from a launch pad on the map*
F3: Removes all blocks from the map *only works from anywhere on the map*
F9: Warps you to the next city map. *only works from anywhere on the map*