Alex Thompson’s review published on Letterboxd:
Uh, well, I guess. What happens when something is really well made and thoroughly complete as a work of art but is also almost entirely without a redeeming factor? I'm not sure I've encountered that yet as this movie has impeccable craft to "recommend" it alongside its depiction of young people being completely stupid-evil. Martyrs is an obvious analogous film, but that movie, too, has its ending which will spark some discussion between viewers. I think this is about as far as I want to go in this kind of direction, though. Each twist of the knife was viscerally felt and nobody can claim that it was all for fun. As an investigation of bullying/mob mentality it is effective, as a torture movie it provokes many grimaces, and as an emotional wringer it matches only films like Funny Games or Bug.