YES i just completed Kingdom Hearts 1 and boy it was tough!! but anyway i completed it now to complete KH2 again.
Well really Tough especialy the Hollow Bastion Gummi Ship Level(the Gummi Ship level going to Hollow Bastion
Only tougher than KH2 in the sense that there was actually less emphasis on mashing the crap out of your X (or O for you importers) button to win battles. And the auto-pilot reaction commands.
lol i remeber the firt time i played it i was really dissapointed that there was no awsome combos like there was in KH2