This movie has a lot to like, it's mysterious, thrilling, gory and often funny. The main actors are all credible and interesting. The cinematography is intriguing and it feels very personal (if a little too dark in certain interior settings.) It plays like a cross between Magnolia and Prisoners, with some It and a few shots reminiscent of The Shining mixed in. Maybe even a bit of Blair Witch and Paranormal Activity. The writer/director did his movie homework.
However, there is a glaring problem. The question of why 17 kids mysteriously disappear into the night is answered in a vague, unsatisfying way. It's not a good reason for the event to occur, and without a good reason for the event, then why make the movie?