Rockford

Unlimited lives:
Load or reset the game, then execute the following BASIC commands before running or restarting the program.
POKE 58199,165
POKE 61881,165
SYS 52992

Unlimited lives (alternate):
Load or reset the game, then execute the following BASIC commands before running or restarting the program.
POKE 58199,165
POKE 61881,165
POKE 63890,165
SYS 52992

Invincibility:
Load or reset the game, then execute the following BASIC commands before running or restarting the program.
POKE 61875,76
POKE 61876,187
POKE 61877,241
SYS 52992

Unlimited time:
Load or reset the game, then execute the following BASIC commands before running or restarting the program.
POKE 63890,165
SYS 52992

One diamond to complete level:
Load or reset the game, then execute the following BASIC commands before running or restarting the program.
POKE 64017,169
POKE 64018,0
SYS 52992