I liked it, but I had some problems with it

The main thing I liked about it was teh fact that the filmmakers didnt forget the movie was about teenagers, they had the same awkward and sloppy logic behind their motivations that most teenagers have, when the is introduced they act like they're on camera but as time goes by they stop acting. My main issue is the sound design at the end, the damn beeping noise is distracting, and after a while the 9/11 operator got annoying and repetitive, I like the idea of having the actual attack told through CCTV, I would have done the same thing had I directed this, but they only show what happens in the library, and they stay too long in those three rooms, yes it's implied that they shot up other places, but I would have like to seen what happened there to, maybe if there was some significance to the library, but it was a location like any other, then again, I'm sure it was done like that due to the budget, I liked it overall but I liked Elephant better, long story short, Elephant works with the idea that it was just another day for the kids main characters, the camera follows them around and they just act like if nothing was gonna happen, once we see the soon to be killers, it all hits you that this is gonna end up bad, and the last act is just tense.

So... grudges attack people.