I think it's an excellent game. The story is great, and well paced. The gameplay is great (for their first try). The cinematics, music, and voiceovers are all very well done. It just feels a little old compared to the sequels. I also don't think that designing your own gummi ship is practical, or even that fun. That's the only thing I would change. Preset designs, and maybe a few addons here and there. That would be fine by me. All in all, I love this game and am not afraid to talk about it.
Kingdom hearts 1 was a good when it came out. Its about 35 hours to beat and a blast to play through. On the downside when I did beat it I felt a little like the game had been thrown together a little bit. Sorta like Chinese food, I kept eating and eating but when I was finally done 20 minutes later I was hungry again...Sadly it took a long time for the Second one to come out and IMO It was a horrible game. The cinemas sometimes were so repetitive and stupid I was embarrassed to play the game in front of others.The Gba game was a little weak IMO but a lot of fans did like it so it is worth looking into. Those are the only ones I have played not sure about the new ones.
I preferred it to KH2. I also, enjoy that while you can rush through the skeleton of the game, there ae also a lot of other optional things. Some of the best bosses in the game don't need to be fought, and aren't ever really mentioned (although Sephiroth is the real superboss in my opinion)