If you enter the code HKFL on the password screen you will be warped to the level after the Skynet destroyer.
Game Genie Codes
Here are some Game Genie Codes
Infinite Lives: 7E02-0405
Full Life Bar: 7E10-C50A
Finish the game and during the credits screen, press B. After the original credits screen, you'll see strange credits like "Thanks to Bill Clinton" and "The Beatles."