Gathering Requirement Question

[KingdomMoose]

So I have a question about the gathering secret ending. In order to unlock it do I need to do the underworld cups like are they even mandatory for it or can I skip them So long as I have a keyhole next to each worlds title? I really don’t want to do the underworld cups. Anybody know?

 

[Bio-Roxas]

I think you just need to complete all of the worlds! (Including Atlantica)

 

[KingdomMoose]

Does that mean I have to go back for the second time or just seal the keyhole.

 

[Grono]

It depends on what your difficulty is. KHWiki is an excellent database for these sorts of things, and there it says that:

For the original game:
You cannot unlock it on beginner.
You must complete Jiminy's Journal on standard.
You must finish the game and complete all worlds on proud.

For the final mix/PS3-4 versions:
You must finish the game and complete all worlds, which means that, yes, you have to beat them the second time.

There you go!

EDIT: Do make note that the rest of the article clearly hasn't been updated too much since its conception. A lot of the theories and possible interpretations do stem back all the way to 2006/2007, so any information pertaining that is obviously not canon and clearly speculation that was later confirmed or denied by Birth by Sleep's existence. It's a cool artifact of the fanbase's past, though.