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

POKE 33242,200 
Unlimited lives (alternate):
Load or reset the game, then execute the following BASIC command before running or restarting the program. 

POKE 30116,173 
Invincibility:
Load or reset the game, then execute the following BASIC command before running or restarting the program. 

POKE 33242,255