Have the Game Boy Advance game Boktai: The Sun is in Your Hand! in the cartridge slot to get the "Sound Data (Boktai)" available for purchase at Bulldog's shop in the Acuna Guild for 3000 Soll.

Have the Game Boy Advance game Boktai 2: Solar Boy Django in the cartridge slot to get the "Sound Data (Boktai 2/Zoktai)" available for purchase at Bulldog's shop in the Acuna Guild for 3000 Soll.

Have the Game Boy Advance game Shin Bokura no Taiyou: Gyakushuu no Sabata in the cartridge slot to get the "Sound Data (Shinbok)" available for purchase at Bulldog's shop in the Acuna Guild for 3000 Soll.