OK, I've arrived at Kingdom Heart's doorstep. Haven't stepped in it, though.

Question is, do i need to do all the gummi ship thing to unlock the secret ending?

And i'm missing some treasure chest from radiant garden.. been through it countless times.. still can't find it...

And the best way to beat sephiroth, please? I've equipped sora with 'once more' ability, but somehow it only worked once..

and about this mini games.. how the heck can i finish the poster thingie in 30 sec? and that cart thing too.. the best time i got was 16 second..