I respect your opinion but feel the total opposite. I enjoyed every world in KH1 (even the controversial ones like Deep Jungle and Atlantica), and think they're all legendary properties. It did a perfect job including everything, from classic to what was relatively recent at the time.
Regarding KH2, I found stuff like Land of Dragons and Beast's Castle a bit boring, and was not looking forward to revisiting some of the returning ones like Agrabah (which is why it astounds me that people want to return there for like a fifth time); NBX and Olympus were cool because they had noticeable expansions.
I guess it's personal preference, and what I'm getting at is that KH2 felt more dull and less colorful to me, but still pretty solid.
I think insofar as the Disney characters' personalities, animations, and interactions with SDG,
KHII really knocked it out of the park.
Running back
KH1, they feel stiff and lifeless, like theme park mascots approximating the real thing.
KHII makes them all feel a lot more genuine, and it's more fun to watch them pal around as a result. Even the gameplay, with Limits and Summons, has a certain flair to it that really encapsulates the characters.
KH1 doesn't have
anything like Sora and Aladdin high-fiving at the end of Speedster, or Stitch breaking the fourth wall to climb all over the HUD, Sora shooting magic from inside a giant Genie's mouth, Jack stepping on a stuffed toy to mourn the box it came in, Tron dancing, Belle elbowing Xaldin in the gut, or Megara dropping prize orbs to help Sora in battle.
I dunno man, feels like it straight-up outclasses the first game in this regard.
With the worlds, I think
KHII more accurately captures each world's individual style and atmosphere, whereas
KH1 feels a bit lifeless. And I can't quite explain it in concrete terms, but
KH1's worlds always felt "darker" to me, which makes them less fun to be in.
