Go see it, don't want to ruin it for you in anyway, I went in without seeing more than one commercial about. Super Punch can shut up about the ending, Super Punch you will not like Beyond The Black Rainbow's end either.
Opinions can be very different, the girl behind me said, "You're out of the movie club" to her friend who chose the film. She's an idiot, she needs to be kicked out of whatever movie club they're in, even if it was a joke.