The story, to start out with, isn't much. 3 friends start dreaming about one day leaving the island that they live on. Then an evil entity known as "The Heartless" comes and take them all to different places. You take the role of Sora, who teams up with Donald Duck and Goofy to find King Mickey. Ok, sounds corny, but it's still a Disney game at its heart.
You move around by using the control stick. Yuo basically just need to smash everything that's in your way by pressing X. You can also items and magic, but those aren't really a priority and sometimes a pain to use.
This game is jam packed with things to do. Besides the main game there are insanely hard secret bosses to test your skills, 99 puppies to find, the search for the various summons, and the list goes on. Overall, this game will keep you busy and I recommend it.