That was an excellent game, the story is mysterious then absolutely spine-chilling!
I do have a remark about the last puzzle though ; as others have said, it's a brutal step in difficulty, even if the logic required is completely sound and achievable. The difficulty is fine in itself, it's just that most of the game does not require you to approach it with this kind of logic. After understanding the filename pattern, all you have to do is figure out who goes where and when, and piece the timeline together. Finding the last hidden scenes requires taking a big step back and change your way of thinking.
That last puzzle is great by itself, but it could be made more approachable by ramping up the difficulty a little in the last acts, so that the player understands what kind of logic the game expects from them.