For those who don't know, it's a documentary about the attempted-murder of a 12 year old girl by her two 12 year old friends. These are middle schoolers who stabbed their friend 17 times. The entire doc feels like it's poorly shining a light on mental illness but almost entirely giving the spotlight to the two attackers, and none to the victim. It feels like it's glorifying what they did and trying to use slenderman as not only a lousy excuse for it, but a cash grab to make a very long unnecessary film.
TL;DR: A doc that's too long and gives too much glory to the two 12 year old children who tried to kill their "friend".