Kingdom Hearts 3 has a secret ending. However, unlocking it won't be easy. Read this page to learn how to unlock the secret movie from which you can learn about the possible future of Sora and the entire Kingdom Hearts universe.
How to unlock the secret ending in Kingdom Hearts 3?
The key to unlock the secret ending in Kingdom Hearts 3 is to take pictures of a specific number of Lucky Marks (Mickey Mouse's symbols) which are hidden in various places across all worlds. Depending on which difficulty level you chose, you will have to:
How to get the secret ending?
Find and take pictures of all the Lucky Marks.
Find and take pictures of a specific number of Lucky Marks (about 50%).
Find and take pictures of a small number of Lucky Marks.
There are about 90 Lucky Marks, hidden in various places across all worlds. Some of them are, e.g. symbols placed on walls, or they are made out of objects. When you come across one of them, take out the Gummi Phone and take a picture of the Lucky Mark. Try to play at least on Standard mode - you won't have to search for every single Lucky Mark.