Kingdom Hearts II is one of the few examples of a perfect sequel. They kept everything that people loved about the first game, and what people disliked they removed or revamped. The plot of the two games fit together perfectly, rather than the plot of KHII feeling as though it was an afterthought that didn't match the story of the original (which was the case with FFX-2). KHII is like what happens when you take a rough gem and put it through a long polishing process. The end result is just beautiful.