Posted 27 May 2007 - 03:27 PM
Well, first off, as I explained in a different thread, Kingdom Hearts is the lone series with the most speculation, in the history of video games. (Only rivaling that of the Triforce in Ocarina Of Time.)
Second to that, the storyline is so deep! It starts as three innocent kids who are dreaming of whats past their walls, to the chaos of the heartless, the Heart of their world, the Darkness in Riku, inheriting the Keyblade, etc. But you don't quite know what the hell is going on, which becomes unveiled to you as the game presses on.
Character development is amazing, as well. How characters become affected by the actions of others. Like how Malificent is able to taint Riku's heart to darkness with hate, and then turn him over to Xehanort.
Many other things as well, but I just woke up, and am much to tired to elaborate.