If you never played chain of memories for the gameboy advance, this would be a good version to play.
The story is the same as the gameboy game, pretty much. It ends after the first game where sora, donald, and goofy wander to castle oblivion. There they must venture up the different floors of the castle, losing current memories to regain lost ones. But everything is not as it seems.....
The gameplay system is still the same, in the way you use cards to attack. You build and customize your deck, attacking with one card at a time or stocking three cards for a combo, gain HP, and acquire new sleights that allow special attacks. For new people, attacking with cards may seem weird, but it's actually really fun. Battles have you facing enemies, letting you stay to fight or escape if you don't feel up to it. The map cards you use let you explore the different rooms, uncovering enemies, treasure, and stories. The environments are extremely well done, especially castle oblivion itself. Audio is very good as well, from music to sound effects to voiceovers.
Now for new stuff added to this version that wasn't in the gameboy game. First, the story takes place before the second game, but sora's voice is from the second game. If you don't like the cards you stocked, you can put them back with R2. Key to rewards cards are still here, but once you use them for every room, they appear again. If you use them again, you will gain all the organization XII enemy cards including Roxas, and you will get keyblade cards from the second game to use. Also in riku's story, you fight Zexion on the island instead of just continuing the story. There are new map cards as well. AND, once you beat each characters stories, you get to watch them again from the main menu in the theatre.
Overall, this is THE adaptation for kingdom hearts. New fans or veterans should definately get this, but I recommend it for everyone. Enjoy!!!