Successfully complete the game to unlock the Sealed Temple.
Defeat Enuo at the Sealed Temple to unlock the Necromancer job and Cloister of the Dead.
Collect all twelve legendary weapons from Kuza Castle. Then, go towards Phantom Village. Just south of there you will see bubbles on the water. Use your sub to dive under the bubbles and you will see the entry to the ??? Cave.
Enter the ??? Cave to unlock the Cannoneer, Gladiator, and Oracle jobs.
Successfully complete the game to unlock the Music Player under the "Extra" option at the main menu.
After a certain number of steps a battle will automatically begin. However, if you quick save, exit, and continue, the step counter is reset. If you only take around five steps, then save and load, you can get all the treasures and leave the castle without encountering a single Jackanapes. You also do not have to run if you are going for the Brave Blade.