Level select:
Type VIVALDI followed by a letter from A through F.
Ending screen:
Type LSD.
Unlimited time:
Load or reset the game, then execute the following BASIC commands before running or restarting the program.
POKE 9004,234
POKE 9005,234
POKE 9006,234
SYS 24586
Unlimited time (alternate):
Load or reset the game, then execute the following BASIC commands before running or restarting the program.
POKE 9004,234
POKE 9005,234
POKE 9006,234
SYS 10723,0
Cheat mode:
Load or reset the game, then execute the following BASIC commands before running or restarting the program.
POKE 9015,173
SYS 8148