Roxy ruined this movie.
The movie was great up until Roxy came along. I love how Frank calls her Juno, because she seriously was Juno, she was Juno throughout the whole movie. No teenager talks like that.
I also didn't understand why she was there. She just seemed like a bored teen with nothing better to do. She didn't care about the meaning of killing those people, she just wanted to kill people who annoyed her in petty ways. She sacrificed herself at the end for no reason. She had a great life with great parents, she was just going through an angsty stage.
She ruined the movie. Frank should have shot her in the face the second she opened her mouth.