Kingdom Hearts II KH II FM + RE:COM Included Features

How to Unlock the Fight against the ES/AU​

To be able to go against this secret boss, first you must have completed the game, which means you must defeat the end boss. Since now you can save after defeating the game's end boss. The other objective would be to defeat the 5 Organization XIII members in their "Absent Silhouette" battles. Their battles can be accessed in different parts of the game worlds. After both of those are done, a portal will be open in Disney Castle "Hall of the CornerStone". The portal leads to the secret boss.

Contributed By: DarkVGKing from GameFAQS​

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KHII Theater Mode​

Theater Mode is an additional feature that appears on the "New Game/Load Game" once you unlock it. In it, you can watch any cutscene from the game in either English or Japanese. Note that the Japanese option includes voices for the scenes that were silent in the game itself.​

Contributed By: KeybladeMasterA from GameFAQs​

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Re: Chain of Memories Theater Mode​

When you first beat Sora's Story, the main screen will have "Theater" as a new selection under "Load." You'll be able to view all the cutscenes in Sora's Story. If you beat Riku's Story, you'll be able to watch all the cutscenes in Riku's Story also.

Contributed By: Afrocious from GameFAQs​

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How To Unlock The New Secret Ending​

Critical Mode: Beat E.S, Complete all silhouette battles, Complete XIII mushrooms

Proud Mode: Beat E.S, Complete XIII mushrooms, Complete Jiminy's journal (Mickey symbol next to it), Beat all silhouette battles

Contributed By: chocobo25 from GameFAQs​

This topic is basically to help those who have some questions how to get the Secret Ending and Theatre Mode. I will update this when I can.

 

Just to add to your Requirements to Unlock Secret Ending for Critical Mode, you also need to collect all 144 crown pieces and complete all the puzzles for them in Jiminy's Journal.

It seems all FAQs are missing this requirement.