Unlockables
Rather than slog through every level in the game's six chapters, reap rewards by entering a six-digit code from the bar at the Mos Eisley Cantina. Admiral Ackbar is unlocked by entering ACK646 in the "Extras" menu, while Greedo can have a chance to shoot first by entering ZZR636. You can replay levels as a furry Ewok by entering EWK785. For levels in the game that require space travel, you can unlock a TIE Fighter by entering DBH897 and an Interceptor with INT729.
Keep in mind that these unlocked characters and vehicles can only be used in levels that have previously been completed.
Ghost Characters
Each level in Star Wars: The Complete Saga features thousands of studs, extra Lego kits and canisters. Collecting every one of these extras will unlock new characters and features, as well as award you with a 100% completion of the game. Exploring levels is easy--it's the enemies that will prevent you from completing your collection of extras. After you have completed the game, visit the bar in Mos Eisley Cantina to purchase one of the following ghost characters: Anakin, Obi-Wan or Yoda. These characters appear as their translucent forms from the end of Return of the Jedi. When you switch to one of these characters during a stage, you will become invincible. No enemies will attack you and your journey to 100% will be easy. Playing as one of the droids such as C3PO or R2-D2 will allow you to move past enemies, but getting in the middle of a blaster battle will still damage your character.
Indiana Jones
For fans of Harrison Ford's other action hero, Indiana Jones can be unlocked as a playable character. To add Indy to your collection of characters, visit the bonus room to the side of the Cantina. Locate the door marked "Trailers" and enter it to bring up a menu of game and movie trailers. Select "Indiana Jones" to view the archeologist in action. Once you've viewed the trailer, you can visit the main bar to purchase Jones for a whopping 50,000 studs. If you find yourself lacking on studs, head to the main room in the Cantina and use your force powers on the blue glasses that litter the floor. Break them all and a bowling ball will spawn. Push the ball with the force and you'll be rewarded with extra studs.