The title refers to more than just the bullet that sets a number of murderous events in motion; it's also John's one shot to change everything. Hoping to use the money to win back his wife and buy his own farm, John soon discovers what we all knew from the start: somebody really dangerous is going to come looking for it. With its sparse script, heavy pitch-black mood and backwoods locale the film often feels like Winter's Bone by way of Cormac McCarthy. It's certainly no less violent and ugly a morality tale as both of those, as bloody altercations occur suddenly and quietly, mostly at the hands of the dead girl's psychotic boyfriend (Jason Isaacs), who has picked up the money trail. John, meanwhile, doesn't just seem unable to get himself out of the deadly predicament, he stands defiant against it even as the walls close in and bodies start to pile up. Soon he's receiving threatening phone calls and threats that the people close to him will pay the price for his mistakes.
Adapted for the screen by Matthew F. Jones, taking from his novel, the film convincingly captures the Stygian murkiness of the locale, darkness that envelopes every character in John's depressing world. The always-great Jeffrey Wright makes the most of limited screen time as John's alcoholic (so much so he can barely walk or see) best friend Simon. In one masterful, heartbreaking scene he encompasses the despair and fatalism that seems to have gripped the entire town. Other casting moves are less successful, including William H. Macy as a pesky lawyer and Ophelia Lovibond as a feisty farmer's daughter who has taken a liking to John. These barely defined characters add little to the story and could probably be left out altogether, as many straggling storylines could have been. In condensing the novel for the screen, Jones has left out crucial details that would better explain some of their questionable motivations.
When tightly focused on Rockwell and the straight-forward nature of John's plight, the film is extremely strong. While we've seen Rockwell take on dramatic roles before, he's barely recognizable here, sporting a scraggly beard and tucked under layers of flannel, his face buried under a baseball cap. He sinks perfectly into the part, and he's completely believable as a trained and experienced frontier man, hacking his freshly-killed dinner with a cleaver and exuding a physicality he's rarely shown. It may seem like a lifetime ago (because it was in Hollywood terms) that Michael Fassbender had been up for the role, and thankfully he passed because it's doubtful anyone could have taken to it better than Rockwell. Even if not everything in the film comes together, it remains an intense, powerful neo-noir with a portentous atmosphere and a portrayal by Rockwell worth seeking out.