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- A reveal ends a plot. It is an essential part of a story, without which there would be no ending, no resolution of conflict, no catharsis … no end credits.
- A twist is an add-on, a luxury. It adds depth to a plot that is already finished, it makes Rashomon what it is - a device to change the point of view of the beholder and makes him/her see things in a different light, without altering what happened beforehand.
The ending to The Sixth Sense is a twist, because it has absolutely no bearing on the plot. It adds a new depth to the story, but it is not essential for it to work. Sure, it makes it a better story, but as audience we are satisfied with how the plot played out already. Our enjoyment of the story is enhanced, which is admittedly a subjective thing.