Monty Mole

Invincibility:
Load or reset the game, then execute the following BASIC command before running or restarting the program.
POKE 9100,205

Unlimited lives:
Load or reset the game, then execute the following BASIC commands before running or restarting the program.
POKE 39273,234
POKE 39274,234

Cheat mode:
Load or reset the game, then execute the following BASIC command before running or restarting the program.
POKE 7863,0