The story picks off straight after the events in the first game where Sora, Donald and Goffy are searching for their lost friends. Sora, Donald and Goofy are chasing Pluto, King Mickey's humble dog down a cross roads. Here a mysterious figure in black approaches Sora and tells him that there is something he needs, but in order to gain it something must be lost.
Sora is confused by what he was just told. So the group travel along the road until they get to a place called Castle Oblivion.
The game play is very different to the first game. It used a card battle system, where you have to use a deck of cards to battle the heartless. You have 3 decks to choose from and each card has a value.
The enemies use cards as well and will tend to card break you a lot. Card break is when you have a card that is lower than the enimies so you won't be able to attack. This will leave you open to an attack.
You can summon characters you have beaten in boss fights or regular summon. When you use a card it will go away but you can reload 3 times so you get the cards back you used.
The graphics for a this game on the GBA are excellent. They are very colourful and the cutscenes are very impressive for GBA standards. There is no voice acting in these scenes only when you fight and lose all your health.
To go into worlds you have to have world cards. These are accessed through Castle Oblivion floors. If you don’t compete all the worlds on a floor they will become available on the next section of the castle. You travel to a lot of the same worlds from the first game, but there is a new one called Twilight Town.
The music is very much the same as Kingdom Hearts because you travel to a lot of the same worlds.
There is a special reward at the end of Sora's story, but I will not spoil it for anyone who has not played it.