Final Fantasy 2 Anniversary Edition Codes -

Completion bonus
Successfully complete the game to unlock the "Art", "Bestiary", "Music Player", and "Soul of Rebirth" options. 

Card mini-game
When in the snowmobile, hold and repeatedly press until a card mini-game starts. The object is to match the images.

 Seals:
Northwest Seal: Break four seals. The fifth one will be the Boss. 
Northeast Seal: Break eight seals. The ninth one will be the Boss. 
South Seal: Break twelve seals. The thirteenth one will be the Boss.