If you're stumped on getting the max score (9999) on Rydia's Mathemagic Minute, there is a easy way. When you're about to begin the minigame, quickly remember the numbers and close your Nintendo DS screen. It will put your Nintendo DS in sleep mode. Write down the numbers you remember and solve the mathemagic. After you find your answer, quickly open up your Nintendo DS and prepare to copy the answer as fast as you can. Keep doing this until you get your max score (9999) and Whyt's Summoner costume at the end.
Goblin outfit
Clear the main story twice.
Ninja
9999 Score in Edge's minigame.
Paladin
9999 Score in Cecil's minigame.
Summoner/Black Mage
9999 Score in Rydia's minigame.
View Credits
In the developer's room in the Dwarve's Castle, inspect the shelf behind the doll in the first room to view the credits.