Never have we seen such a great Disney game on ANY console. Kingdom Hearts is one-of-a-kind.
Aside from the main story, there are tournaments to enter in the Olympus Colliseum, and even a secret, almost unbeattable (seriously, it took me about 50-100 times to beat him) boss battle against Sephiroth. You can also help find the 101 dalmations, which are in treasure chests in various different worlds.
The game definetly has very simple controls, which is very nice for a game like this. You can also have different attack skills like this move where Sora throws his blade at an enemy kind of like a boomerang. But there are also gruoup skills, like high-jump, or glide, or various other things that improve your jump height and such.
The game is one that, if your playing on easy and bypass all of the cutscenes, that it will take you a little less than 20 hours to complete it, but it should take you 30-40 hours maybe to beat the game. That is, if you do the main story and then do a few of the extra things in the game.
Kingdom Hearts is a great Role-playing experience, that any RPG lovers would love, if your not that into RPG's, or don't like Disny or Square Enix much, rent the game first. But if your looking for a good, fun game, then this is the one for you.