I have to agree with the other, few, reviewers here....why this film has barely a "4" rating is beyond me. It's about twice that good. Not only is it an interesting story, the characters are well-drawn and complex, the action is very well staged and performed, and even the special effects are creepy and effective.
Julian and John (Shane Dean and Slade Hall) are well-worn survivalists. Their idea of a kick-ass weekend is to walk for a few days into Arizona desert with nothing but a couple bottles of water. Julian seems to have taken these treks a bit more seriously over the years, and balks when John invites his younger loud-mouthed bud Paul (Cavin Gray Schneider) along for their latest adventure into the Arizona Coconino (?) forest (a new one on me, but a very cool location).
There's good tension between them as Julian and Paul constantly tear-down and one-up each other with John desperately trying to referee. Much like "Deliverance," however, the trio encounter an unexpected turn of events that has them fighting for their lives for two-thirds of the film.
I'd never seen any of these actors before, and I was extremely impressed with all of them, particularly Shane Dean's Julian, who takes a role that could have easily been written off into crazy-ville and instead makes it compelling and oddly tragic.
What really blew me away were the dream and drug-infused (via peyote, of course) sequences. For a low-budget movie, these were extremely creepy and vividly rendered.
The ending is chilling, and not easy to shake. The only minor quibble I have with the film is many of the insider survivalist techniques. They're not really "explained" very well, and there's ample opportunity to do so, given that Paul's character is a newbie.
But this is a minor flaw in an otherwise trippy, tense experience.