At the main menu, select the "New Game" option, then enter "GREYTHERAT" as saved game name. All levels, including the bonus levels, will be unlocked. Enter "M1A2U3L4!?" as a saved game name to unlock all levels until Darth Maul.
Defeat Darth Maul in level 25 to unlock the Battle Royal mission, where you have to fight eight other Jedi Masters in the Saber Arena.
Defeat a character in the Jedi Arena during the game to unlock him or her in versus mode.
