Use the "Save Data" option to save the game ten times. Then, an "Edit Mode" option will now be available.
Expert mode (Pac Attack)
Select arrange mode. Then at the difficulty selection screen, highlight "Veteran", hold Right and press Circle.
New Pac-Attack Godhand Mode
In the new version of Pac-Attack, you can enter Godhand mode by holding right and selecting "Veteran". If done correctly, you'll see "Godhand?" flash on-screen. In this mode, you start at level 900 and try to clear level 999. However, the drop speed is fast and Pac-Man only appears every tenth piece