Tetsuya Nomura, director of the Kingdom Hearts franchise, recently hinted at a secret video at the end of Kingdom Hearts: Birth by Sleep, which everyone could look forward to watching. The catch is, this is a secret ending to Kingdom Hearts: Birth by Sleep itself, not a hidden trailer like the secret videos at the end of the Final Mix titles.
Well then, please continue to have fun. Oh also, if you don’t watch all of the story that happens before the secret movie, and just watch only the secret movie, you won’t understand any of it. So please get there on your own.
For what it’s worth, Laura already spoilt the secret ending for herself without playing the game and says it was exactly what she expected. So, unless there’s a third, undiscovered video in there somewhere, prepare for potential disappointment.