I detest the modern horror film, especially those with gratuitous violence. I watched this one because the violence was reported to be NOT gratuitous. It wasn't, but it fell short of being good.
It's obvious that the two boys are frustrated in dealing with girls. They understand that to play the game, you have to be "nice" to girls and "obey" them, and if you're poor, ugly and awkward you have to debase yourself even more. Thus the discovery of a "living dead girl" is a dream come true; a girl they can have sex with, without pretending to be "nice." It's been suggested that the film is actually a fantasy, or a metaphor playing out in the boys' heads. Maybe so, but the filmmakers didn't wish to make that clear. In fact, we don't really get to understand the boys enough to figure out why they might turn sadistic and violent. Is this what is inside every rejected, lonely nerd? Are we all Harris and Klebold just waiting for an occasion to strike? We don't know, and the film doesn't want to tell us.
Incomplete, fragmented and unclear storytelling do not make a film "deep." If this film had been more coherent, it might have been celebrated despite the gore, cursing and near inaudible audio engineering. As it is, a 4 is generous.