Here are the cheats and hints for Kingdom Hearts : Chain of Memory on GBA.
Unlockable: Riku’s Story
completed the story mode with Sora.
Unlockable: Summon Cards
* Take Pooh out of the 100 Acre Woods: Bambi Card
* Defeat Hades: Cloud card
* Beat Monstro level: Dumbo Card
* Beat Jafar: Genie Card
* Beat Guard Armor: Simba Summon Card
* Beat Captain Hook: Tinkerbell Card
* Mushu card: Open key to rewards in Hollow Bastian
* Riku card: beat Riku Replica the 4th time
* Confuse: talk to Piglet in the 100 acre woods
* Blazing Donald skill: open key to Rewards in Agrabah
* Omnislash: Stock up 3 cloud cards
Unlockable: Alternate Title Screen
Complete Sora’s Story.
Hint: White mushrooms
Go to a White room. Then search for white mushroom enemies. Get a battle with it. The enemies won’t attack you. Wait until you see a bulb above their mushroom. Attack on that mushroom with lightning attack. After a while, they give you experience points, and a glowing P. If you touch it roulette starts and changes a card into a premium card.
Go to 100 acre wood. Then find Roo and help him out of the hole. The Elixir will quick-load both your attack cards and your magic cards. He will also add to your journal.
Hint: Defeat Marluxia
Before face Marluxia, make sure you have maximum health and 820 card power.Pur three or four cure cards. Then destroy the two swords.Normally, he don’t care to them. Finally, cardbreak him. You will then see the lock on him; then attack.
Note: You must cardbreak him, or you can’t attack him. You can tell you can attack by when the lock shows on him.
Platform: Game Boy Advance
Tags: Kingdom Hearts, Kingdom Hearts : Chain of Memory