SNAKES, WHY DID IT HAVE TO BE SNAKES? I suspect folks will want to talk about Prisoners, which is sort of Harlan Coben crossed with Terrence Malick, and I have a question, but to even ask it is so spoilery that it has to be after the break.
So, in the end, the girls were taken by Melissa Leo's character, who had been abducting and killing kids for years, and Paul Dano was her first victim, who she adopted as her "nephew," despite never involving him in her subsequent crimes. (Apparently, her motivation is to "test people's faith" and see if killing their children turns them into "demons"--it doesn't make a whole lot of sense, but whatever.) Hugh Jackman figures out she's behind it, but she captures him, drugs him, and tosses him into a secret crawlspace dug out in the backyard hidden under an old car. There, he finds his daughter's "emergency danger whistle," his daughter having been moved to another space.
Detective Loki (Gyllenhaal) figures things out shortly thereafter, frees Jackman's daughter (the other girl had escaped earlier), and kills Leo. He doesn't find Jackman. A few days later, the cops are digging up the yard, finding many strange things buried in the yard, but haven't uncovered the crawlspace, and the crime scene techs note it will take months to dig up the yard because the ground is freezing. Loki hears the whistle from the ground, turns, and SMASH CUT TO CREDITS.
So, the question is--does Loki (1) free Jackman and have him stand trial for the torture of Dano (for which he has an airtight case) or (2) leave Jackman to die in the crawl space as "punishment" for what he did wrong? I think the movie can arguably support either reading, and I'm not sure if that's because it's smartly ambiguous, or unsure of what it's actually triyng to do.