Huge pacing problems.
This movie had huge pacing problems. The first half of the movie spent minutes stretching out what amounted to just seconds worth of content. The last half of the movie, with the kids in the school, was very fractured and severely lacked cohesion.
Some comments on audience reactions:
For some reason, this movie seems to be stirring up lots of God comments. I don't really see what God has to do with all this. The whole thing about asking a victim if they believe in God before killing them is a Hollywood villain cliche. That's why the kid said it--he was a movie buff immitating his favorite Hollywood villains. Point isn't "the TV made him do it;" it's that there's no deep significance to his words--he simply parroted something he thought sounded cool.
Some people are saying everyone should be accepting of "different" people. Thing is, a big part of being different is NOT wanting to be accepted. This duo in particular railed on mainstream interests and beliefs--they believed they were smarter and better than everyone else, and self-consciously DID NOT WANT TO BE ACCEPTED BY THE MAINSTREAM! Textbook teenage rebellion, folks!
Finally, stop saying, "I don't support what these guys did, but...." There's no "but." You either find what they did excusable or you do not. Don't be a hypocrite and say you find it inexcusable then immediately turn around and start making excuses for it. If you're ashamed of your beliefs, don't spread them.