 Chain of Memories was announced along with Kingdom Hearts II at the Tokyo Game Show in September 2003 . Initial details included the switch to 2D graphics , the use of cards to perform attacks , and that compressed movies would be utilized in some cut scenes . The cut scene animations were rendered using the graphical engine of the PlayStation 2 iteration and then encoded for the Game Boy Advance by using a technology developed by Japanese company , AM3 . To help market the game , Disney and Square Enix launched official Japanese websites . A playable demo was first made available to the public at the 2003 Jump Festa in Japan ; this demo and subsequent demos highlighted the card @-@ based combat system . Aside from information gathered from the opening sequences , most details regarding the story were kept secret until the release . 
