Extra menu:
Complete the indicated task to unlock the corresponding option in the "Extra" menu.

Art Gallery:
Successfully complete the game. This option allows all unlocked game art to be viewed.

Bestiary:
Successfully complete the game. This option displays information all each type of monster that you have defeated.

Music Player:
Successfully complete the game. This option allows all songs from the game to be replayed.

Time Chamber:
Complete the Labyrinth of Time. This options allows you to replay any completed floor from the Labyrinth of Time.

Art Galleries:
Complete the indicated task to unlock more entries in the Art Gallery menu.

Art Gallery 01-56: Have all monsters in the Bestiary.
Art Gallery 57: Complete floors 1-10 in Time Chamber with unlock blue seal.
Art Gallery 58: Complete floors 11-20 in Time Chamber with unlock blue seal.
Art Gallery 59: Complete floors 21-30 in Time Chamber with unlock blue seal.
Art Gallery 60-67: Complete the game.
Art Gallery 68-75: Complete the game.
Art Gallery 76: Complete the game twice, including 30 floors in Time Chamber and all of monsters in Bestiary.

Bonus puzzle game:
Enter the ship, hold Circle and press X (55). Arrange the tiles in order from 1 to 15 to collect 100 Gold.