Continue game play:
Enter FLUFOMATIC as a name at the high score screen to start the next game on the last level played. 

Cheat mode:
Load or reset the game, then execute the following BASIC commands before running or restarting the program. 

POKE 27931,173
POKE 11193,173
POKE 10886,173
SYS 2057 
Unlimited lives, bombs, and lasers:
Load or reset the game, then execute the following BASIC commands before running or restarting the program. 

POKE 1409,0
POKE 10073,0