Instructions
Obtain enough studs throughout each of the 17 levels to obtain a "True Jedi" status. The studs are the small gold and silver pieces you collect when breaking piles of bricks. A progress bar appears at the top of the page showing how many more studs you need to obtain before receiving the "True Jedi" status for each level.
Enter the "?" Door in the main lobby of the video game. This is where you choose what level to play. The "?" ends up being a door to "Episode IV A New Hope."
Complete the single Episode IV level. You play as Darth Vader throughout this entire level. Your mission in this level is just to obtain as many studs as you can.
Receive Darth Vader as a playable character upon finishing the level. You can now go back to any previous level and use the character.