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

POKE 7892,255 
Unlimited lives:
Load or reset the game, then execute the following BASIC command before running or restarting the program. 

POKE 2710,44 
Set number of lives:
Load or reset the game, then execute the following BASIC command before running or restarting the program. Note: X represents the desired number of lives. 

POKE 7636,X