Kingdom Hearts: Chain of Memories is an action role-playing video game co-developed by Square Enix and Jupiter, and published by Square Enix in 2004 for the Game Boy Advance.
After the events of KH, Sora, Donald, and Goofy chase Pluto down a long path until they take a break. During the night, Sora comes across a crossroad, and suddenly a black hooded unknown appears and tells Sora that he must gain back what he lost but give up something in return. Just then, Sora shows up at Castle Oblivion, where Donald and Goofy are turned into cards, and his memories are lost. Now he must progress through the castle and revisit the worlds to regain his memories and find out what’s going on.
This game is an Action RPG, with attacks based on cards. With the cards, you can attack, use items, summon allies, and use spells. Each card has a number, and when two cards are used simultaneously, the card with the most attack points wins. Also, you can combine cards into combos, up to three cards at once. This is called a stocking. If you stock-specific cards, you can unleash a special attack called sleight. By leveling up, you learn new sleights. This opens up lots of possibilities, and you have lots of sleights at your disposal. If you run out of cards, you may reload or use an item card to get ’em back.
The cards available to your use at battle can be changed whenever you want by editing the deck. You get new cards on the levels, from chests, or from Moogle Shops. There are Red Cards, Blue Cards, Green Cards, and Black Cards. The Red Cards are the Attack Cards, and they alter the power of Sora’s Keyblade. The Blue Cards are Spell/Summon Cards, and they cast a spell or summon an ally. The Green Cards are Item or Friend Cards, and they either use an item or summon a friend. The Friend Cards cannot be gotten outside battle, they just pop up on the battlefield. The Black Cards are the Enemy Cards, and they don’t go with the main deck, even though they count as a card to the deck. These cards cannot be reloaded, and activate a special effect that lasts some attacks or reloads.