Special Power Spell Charm:
Hold L1 + L2 + R1 + R2 while starting a new game at the title screen. A power spell charm with unlimited charges will be available.

Alternate Costume:
Hold L1 + R2 + Select + Triangle while starting a new game at the title screen to wear a school uniform during game play. Hold L1 + R1 + Select + Square for another costume.

Sound Test:
Press Left, Circle, Down, Triangle, Right, Square, Up, X, L1, R2, L2, R1 + Start at the title screen to unlock the "Sound Test" selection on the option screen.

Extra Mode:
Successfully beat the game with an "A" rank to unlock an "Extra mode" option in the pamphlet menu. This allows the game to be played in time attack and score attack modes.

Guide Option:
Unlock all thirteen endings to unlock a "Guide" option in the pamphlet menu. This allows the biographies of each character to be viewed.

Thanks to Revolution reader Neadow-2!