Overlander

Unlimited lives:
Load or reset the game, then execute the following BASIC command before running or restarting the program.
POKE 13398,44

Unlimited fuel:
Load or reset the game, then execute the following BASIC command before running or restarting the program.
POKE 6337,174

Unlimited fuel (alternate):
Load or reset the game, then execute the following BASIC command before running or restarting the program.
POKE 6337,173

Level Select:
Load or reset the game, then execute the following BASIC command before running or restarting the program.
Note: X represents the level number from 0 through 4.
POKE 1847,X