I swear Kingdom Hearts II is harder than I remember. Devastators are the worst. So they have two forms. The first form is a tank which fires energy spheres at you at various tempos, which can be rather hard to avoid. Then it can transform into a floating tank which relentlessly pursues you. But the worst thing is when it transforms. It tries to get close to you and then spams a lightning fritz which if it gets you, is impossible to get out of and hurts like hell.

And this is on top of any other heartless you're trying to focus in on. Infuriating!

Berserkers, the nobody enemy, are also frustrating because you can't really hurt them until you block their (hard-hitting) attacks.