Writer/Director S. Craig Zahler is to be commended both for his unique story and the way he was able to interest some notable actors to star in it under his own direction. Certainly the result is a rather odd cup of tea, not necessarily to the tastes of a broad audience, but there is a lot here to like or at least admire. Zahler's dialogue is deliberately idiosyncratic, with its formal cadences and unusual vocabulary choices, but it's in service to a rather plodding 'quest' storyline that builds to a rushed (albeit gruesome) finale.
Along the way there are a few false steps. It's not a very suspenseful trek that the heroes make to rescue the townspeople abducted by the cannibals; the riding scenes (then walking after their horses are stolen) and bivouacs play out one after the other with little sense of pacing. In fact, their main function seems to be to pad out the film's running time.
By the time the cannibals' lair has been discovered, the ensuing violence happens in discrete bursts of action with no build-up to a climax. Little enlightenment about the tribe, its origin and intentions, including whether there are enough survivors to remain a threat, is provided either visually or verbally.
Performances by the cast, especially Kurt Russell as the sheriff and Richard Jenkins as his deputy, are an asset. However, Matthew Fox's character proves somewhat enigmatic and wooden. And Patrick Wilson, as the injured husband seeking to rescue his kidnapped wife, is okay but has done much more compelling work elsewhere.
A couple of other minuses are the flat cinematography of mundane Southern California desert locations, and Zahler's apparent disinterest in close-ups. But the cannibals are pretty scary, and there's one spectacular prosthetic makeup effect like nothing I've ever seen.
Overall, Zahler shows considerable promise as an off-the-beaten-path type of filmmaker, and viewers will probably want to keep an eye out for his next project.