To access the "???" option in the pamphlet menu, beat the game with an "A" ending. This reveals a new "Extra Mode", which contains selections for "Time Attack" and "Score Attack" mini-games.
At the title screen, press Left, Circle, Down, Triangle, Right, Square, Up, X, L1, R2, L2, R1 + Start. A "Sound Test" option will appear under "Option Mode".
Unlimited Power Spell
At the title screen, hold L1 + L2 + R1 + R2 and start a game. Then, a power spell charm with unlimited uses will be available as soon as the game begins.
View Character Biographies
Unlock all thirteen endings, then select "Pamphlet" mode. Now a new "Guide" option will allow data for each character to be displayed.
Wear School Uniform
At the title screen, hold L1 + R2 + Select + Triangle and start a game.