To unlock the "?" door found at the episode selection room, you must achieve True Jedi Status in all of the seventeen levels, 6 in Episode 1, 5 in Episode 2, and 6 in Episode 3. True Jedi Status is the black/golden bar that appears at the top of your screen during any episode level. The way to fill up this bar is by getting a certain amount of studs during that level (each lvl has a different required stud amount.) Once all levels have True Jedi Status, the "?" door will be unlocked.