Spirits
Sixteen spirits exist in the game, each of which must be unlocked before it is usable. "Adhesive Explosive," "Jerry Beans Man" and "Oscillo Hero #2" are starter spirits, which can be found in the beginning of the game at the well. "Hane-Hane" and "Star Boy" are unlocked after beating Bastion twice. "Skelengel" and "Acrobat Monkey" are unlocked randomly after defeating Kagemaru. "Soitsu" and "Ebon Magician Curran" are unlocked after the abandoned dorm events. "Babycerasaurus," "Beelze Frog" and "Blast Asmodian" are unlocked once the tournament finalists have been chosen. "Batteryman C," "Batteryman D," "Dragon Capture Jar" and "White Magician Pikeru" are unlocked only after the entire game has been completed.
Duel Disks
Unlock in-game Duel Disks by repeatedly defeating specific foes. Depending on your exact spirit, the number of times each foe must be defeated vary. Beat Professor Banner for the Alchemy Disk, Tania for the Amazonness Disk, Admiral for the Gorgeous Disk, Kaibaman for the Kaibaman Disk, Abidos for the Pharaoh Disk and Camula for the Vampire Disk. Link up with Nightmare Troubador to receive the Cheap Duel Disk.
Uniforms
Unlock alternate uniforms by defeating specific enemies a certain number of times. The number of wins required against each enemy varies depending on your specific spirit. Beat Fonda for the Academy Jersey, Chazz for the Black Uniform and North Academy Coat, Dark Zane for the Blue Uniform, Crowler for the Duel Coat, Atticus for the Hawaiian Shirt, Kaibaman for the Kaibaman Coat, Titan for the Titan Coat and Professor Satyr for the Yellow Uniform. Link up with Nightmare Troubador for the Stuffy Collared Shirt and simply duel with Chumley for the plain Suit.
Action Replay Codes
The Action Replay peripheral device is compatible with "Yu-Gi-Oh! GX: Spirit Caller." To enable Action Replay codes, enter the master code of "03808074 ebafd7e2." Once enabled, use "122cf08c 00001f40 122d1a3c 00001f40" for unlimited hit points, "021058cc 000f423f" for unlimited duelist points, "122cf8f4 00000000 122d1a40 00000000" to instantly win any duel, 822cf8f4 00000001 122cf8f4 00000001 822d1a40 00000001 122d1a40 00000001" to defeat enemies with one hit and "021058c0 0000ffff" for a quick level upgrade.