This cheat will allow you to start at any mission in the game by doing the following:
1. Go to the option screen and highlight PASSWORD and press Enter.
2. In the space next to PASSWORD type ZZZCYX.
3. A new menu item will appear on top of all of the other options called LEVEL SELECT: to allow you to select 9 different levels to start from.
4. Highlight this new option and use the left and right arrow keys to select a level.
5. Highlight BACK TO MAIN and start the game.