I have literally only one complaint about this. It was marketed as being shot documentary style with hand held cameras. It either needed to stick with that the whole way through or just shoot it normally. The mixing of the two didn't really work. It made it seem like the director was all in for the documentary style, and then realized half way through filming that doing that only wouldn't totally work with the story he wanted to tell, so he just started throwing normal shots in until they took up half of the movie. But. Other than that, I thought this was brilliant. You really get to see the two main characters fall into a rabbit hole of sorts. Neither they nor the audience fully understand everything that's going on, and I think that makes it even scarier. It's unapologetically violent and gritty, which actually really worked for me. I liked that the script did some time jumps, like we're seeing mini-episodes in these cops' lives. On top of all that, the acting is awesome. Jake Gyllenhaal and Michael Pena are fantastic. They have an easy chemistry and banter to where you really believe that they've been friends for a long time. Speaking of their banter, it really broke up some of the heavier scenes, which was really nice, and then to find out that most of it was improvised made it even better. Anna Kendrick got to show a little of her goofy side and America Ferrera got to show a little of her badass side. I don't want to ruin the ending but I cried. A lot. A definite recommendation.