A great, great game. By far one of the most wonderful games on the gba.
Gameplay: Sora's memories are changed into cards, allowing the most intuitive battle system in the series. You can build your own deck off of existing cards, or buy new cards from moogles. You can play three cards at once by combing cards, called sleights. The game provides the right amount of challenge. It strikes a perfect balance between action and strategy.
Story: The game takes place directly after Kingdom Hearts. You meet a man who tells you that you can find something important to you. But, you have to lose something. You then traverse the floors of Castle Oblivion, through one of the most well-thought out stories I've ever read. The ending seems perfect, striking the perfect balance of happiness and sadness.
Graphics: The game starts out with a 3D full motion video that could be on the ps2. Yeah, its that amazing. Then, you play as very colorful sprites that perfectly fits the game boy advance style.
Music: The music is amazing. It combines music from the first game and new music to create wonderful music to listen to as you play. It even cranks out Utada Hikaru's "Simple and Clean" full blast during the ending.
Fun: Some of the most fun on the game boy. No doubt about it.
Overall: Kingdom Hearts CoM(Chain of Memories) is an amazing game. the gameplay is awesome, the graphics are great, and the music is wonderful. Definitely pick this one up.