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

POKE 5714,173 
Invincibility:
Load or reset the game, then execute the following BASIC command before running or restarting the program. 

POKE 5643,255 
Unlimited lives:
Load or reset the game, then execute the following BASIC command before running or restarting the program. 

POKE 41624,165