I saw this movie on Friday and I'm thinking about it right now, trying to go to bed, but filled with excited thoughts about this film.
I absolutely loved it. The first 20 or so minutes were slow. Really slow. Then the movie becomes intriguing. I started to enjoy it a little bit. Then the last 30-45 minutes gripped the heck out of me. The final act / act-and-a-half were mind-blowing to me.
The three things I loved the most about the movie (spoilers):
#1: The medical examiner arguing with Elizabeth Olsen's character, insisting that he can't in good conscience label Natalie's death as a homocide. Natalie's death most likely was the result of foul play, and ruling the death as a homocide is the only way to get the FBI to help, but the M.E. won't budge. Olsen's frustration in the scene was endearing to me.
#2: The last 30-45 minutes, which started just as Olsen and Jeremy Renner's characters (along with other officers) arrived at the fuel company where Matt worked. This was incredibly intense. I was god damn impressed. Things started to get real heavy the instant that cop said "Hey wait a minute, why are you guys flanking me" and nearly everyone pulled out their guns. Thrilling - the scene ended with everyone holstering their weapons, so there was no bloodshed just yet. Was gripping though.
#3: More of a continuation of #2, as it also involves the final part of the movie: Then, another part I loved was Olsen knocking on the cabin door, then the film switching to the flashback scene. I haven't seen a movie do a flashback quite like that before. The uniqueness of the flashback scene (or the way it was woven into the story), coupled with the shockingly brutal, tragic, and incredibly sad content of the flashback - together they put me on the edge of my seat.
Can't stop thinking about the movie.
I'd give it a 10/10. It was a slow burn of a movie, with gripping tension and a great, compelling final act.