This game is the best game of the year. You can play this game without playing the first game, but if you get lost it would be nice to check it out. If your still lost play chain of memories, that game will explain Axel and the organization more. It will also explain why Sora, Donald, and Goofy are in those pods at the beginning of the game and more. KH2 has a better battle systems, the camera is more pulled back, and the "drive mode" makes the game more strategy than the last. More worlds, villains, keyblades, and powers. In this one you start the game as Roxas. After you start playing as Sora then the game starts making sense to an extent. They even made a hint to a KH3!
This game is one of the best rpg games ever made. The game play is unbelievable, and the graphics are better than ever. The only problem I had was from time to time the camera would do whatever it wanted and began to wonder. Other than that, this game is truly amazing, both graphically, control wise, and difficulty wise. It's easy to just pick up and go for both the hardcore and amateur players alike. This may be one of the better games ever in Playstation 2 history and is a must own for any gamer.
Kingdom Hearts II is the best game that I've played in a long. I would recommend it to anyone. But make sure to have played Kingdom Hearts I first. Chain of Memories isn't necessary to play, but it would neither enhance nor degrade your playing experience.
They game variety is simply amazing. Even though most of the worlds are the same ones you've been to there are more areas and much more stuff to do, and mini-games out the wazoo.
It was also the first game to ever make me cry. I cried at the end. It was just that great of a story.
I would heartily recommend it to anyone who enjoys video games of any kind.