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

POKE 47270,173
SYS 828 

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

POKE 36445,173
SYS 828 

No enemies:
Load or reset the game, then execute the following BASIC command before running or restarting the program. 

POKE 41603,208
SYS 828