Bombo

Cheat mode:
Type  SCORE  at the title screen to enable cheat mode. The phrase CHEAT MODE OPERATIVE will appear to confirm correct code entry. Your character will be invincible when game play begins.
Hold  [Run/Stop]  to freeze the monsters and allow your character to pass through them. Release  [Run/Stop] and press  Fire  to return to normal game play.

Cheat mode (alternate):
Load or reset the game, then execute the following BASIC commands before running or restarting the program.
POKE 11417,173
SYS 387

Invincibility:
Load or reset the game, then execute the following BASIC commands before running or restarting the program.
POKE 11745,140
POKE 38644,255
SYS 38610