You´re depressed because you found out about the actor based reality. Realizing that some of your favorite actors are actually playing people you have been told are real who turn up on tv and then represent what you had always hoped, is a shock which results in periodic depression. Once you start to recover from the depression your sanity starts to return. Just remember that just because actors can cross ethical boundaries does not have to mean that all actors do, or that any of it has anything to do with you. The best actors are agenda - free ones who refuse to be part of any of the political bullshit. They are the ones who deliver the best performance like the ones who are part of this film.

It's a mirror. Her reflection looks like it walks through an open doorway but it's just a mirror. The jigsaw piece was in her hand already...she didn't pick it up from under the table. It had been slid to her from the other side of the door while she was locking it. The way her reflection moves and how we see her sit and lean forward from behind makes your interpretation understandable though.

It's already late. The monster probably just doesn't want her to be busy with the puzzle all night.

But the funny it this ::playing with the human curiosity. More strong than supposing that "who invaded my apart?". If she lives with someone?

That's the point... We're afraid much more of what we don't know :>

Everything you said is true, but it is the third puzzle piece.

What if you had a GF and the puzzle was a present for you to find something? Uh uh? Gotcha there! You would call the cops and in the end it would be for nothing