KINGDOM HEARTS Chain of Memories is the most unique game in the series. Due to whatever reason it is on the Game Boy Advance, it has limited control buttons. In Chain of Memories, all of Sora’s actions are controlled by the use of the cards that are in the player’s deck, making each heartless or boss battle a mini card game with the objective being landing the most attacks on the opponent. Whoever throws out the highest numbered card is allowed to make and attack, but an attack can be broken at any time by a card numbered higher than the one thrown out, or by a zero card.

Actions controlled by cards:
Attacking:
Magic (Fire, Thunder, Blizzard, Cure, Aero, Gravity)
Friend (Donald, Goofy, Aladdin, Peter Pan, Beast, Jack Skellington, Ariel, Pluto, Mickey Mouse)
Summon (Cloud, Simba, Mushu, Bambi, Dumbo, Genie, Tinker Belle)
Enemy Card (gives a brief bonus to user)
Items (usually restores cards)
Blank card (reshuffle)

Whenever a card is used to goes to a figurative discard pile, and the only way to retrieve the card is by reshuffling the deck (using the blank card.) For Sora, each time Sora uses the reshuffle; it takes longer the next time. Riku’s reshuffle remains constant.

Additionally, cards are used as keys to rooms. In order to unlock a normal room, a card numbered the same or higher than the door must be used. For an event room, a card for that specific room + whatever amount need per room must be used.

Controls:
A – Use card
B – Jump
L – Shuffle deck left
R – Shuffle deck right
L+R – Stock cards, use stocked cards (when 3 are stocked)
Start – Pause
Select – Switch to enemy cards

Sleights:
Sora’s ability attacks are replaced in this game by “sleights.” When Sora stocks up 3 cards, if the total of those cards reaches a certain number Sora will use a sleight. Some sleights are triggered by specific cards, not number, such as trinity limit, which is activated when a Keyblade, Donald, and Goofy cards are stocked.

Differences between Sora and Riku:
- As Sora, the player is given the option to build his/her own deck, while Riku is given a different unchangeable deck in each world.
- Riku can jump considerably higher than Sora.
- Riku is not allowed to use sleights unless he is in Dark form.
- Riku cannot heal himself.
- Riku is granted the ability to use “Dark Form,” which allows him to use sleights. Riku transforms to dark form whenever he breaks enough cards. The difference between the card he used to break a card and the broken card’s number is added to a counter that transforms Riku when it reaches a high enough number.