The unsettling framing and every shot being off kilter, but not inherently handheld, makes you feel unsafe the entire watch through. The idea the story hands you is genuinely freaky no matter how you decide you see it and it really allows the audience to interpret it in a way that is so necessary for what they present you with.
I've shown this to so many people already because it's gotten in my head so well, and even if it's not your favorite type of horror, you'll still fall in love with the very human essence of the story. I found it scary because I really enjoy paranoia, but even if it doesn't freak you out it's still amazing. This deserves so much love and attention, amazing work from all parties involved.
