Walter Hill never made topical films - at least not deliberately. Instead, the action stylist, now 79 and still making movies (his latest, the Western Dead for A Dollar, is due out next year), has almost without exception made genre pictures about relationships between masculine men and the codes they live by. Contemporary matters just don’t seem to interest Hill; if he isn’t making films set in the American past, he’s bringing out-of-time archetypes into modern settings where the law seems curiously Old West.

A tough B movie shot and told in the filmmaker’s beautifully precise early style, 1981’s Southern Comfort is classic Walter Hill, yet critics at the time insisted it was also something more. Despite the director’s own protestations, this was a Vietnam War allegory, a camo-coloured swamp horror with blatant parallels to America’s great foreign policy catastrophe of the ‘60s and ‘70s. Set in 1973, the film follows a squad of National Guardsmen on weekend manoeuvres in a Louisiana bayou, where the soldiers end up being picked off one by one by the locals. Incompetent leadership, failure in planning and unfamiliarity with the environment end in bloody mission failure. Roger Ebert, for one, saw an obvious metaphor for the “uselessness of American technology against the Viet Cong”; Hill meanwhile maintains to this day that he just wanted to make a backwoods horror about men.

If Southern Comfort indeed really were “just” a horror movie about the complexities of male behaviour, then it would be one of the best of its kind. Made at a time when studios couldn’t churn out enough suburban slashers following the success of Halloween (1978), Southern Comfort unfashionably presented as its victims not small town teenagers pursued by a supernatural killer in the dead of night, but grown men hunted in the impenetrable woodland terrain of very human bogeymen, doubly chilling because they stalk the protagonists in daylight and still remain largely unseen. Apparently out of step with what horror fans wanted in the age of Freddy and Jason, Southern Comfort, in the words of Hill, “didn’t make a fucking nickel anywhere” on release. Four decades later, though, it endures as a rare hunk of American folk horror.

Shooting on location in Louisiana’s Caddo Lake, cinematographer Andrew Laszlo frames the bayou as at once anonymous, picturesque and ominous. The landscape looks almost alien: ubiquitous hanging moss; tea-coloured water; bone-dry ancient cypress trees sticking out of the earth like giant, fossilised femurs. To the film’s gun-toting, French-speaking Cajuns, such terrain is familiar and apparently easily navigable, but it’s only hostile to Hill’s weekend soldiers, who find shifting waterways, medieval traps and gilet-wearing ghosts taking rifle shots from deep in the woods.

Having brought Alien to the screen as a producer and uncredited screenwriter two years prior, Hill repeats that film’s formula by making Southern Comfort star-free - all the better for keeping the viewer in the dark as to who (if anyone) will survive to the end. Investing the Guards with the hard-won charisma of the perpetual character actor are some great B faces of American cinema: the handsomely severe-looking Peter Coyote; perma-scowler Fred Ward; stretched-out Klaus Kinski lookalike Keith Carradine; Southern-fried everyguy Powers Boothe, his hard face and bulging cheeks giving him the look of a man with a mouthful of wasps.

Outwardly, these are all typical Walter Hill tough guys. What makes Southern Comfort unique in a filmography packed with movies about cool, hard-ass male professionals, though, is that Hill’s “heroes” here are fragile, self-sabotaging individuals who happen to be lousy at their jobs - and whose macho natures ultimately prove their downfall. Lewis Smith’s Pvt Stuckey firing blanks at local hunters as a prank initiates the Guards’ conflict with the Cajuns; Les Lannom’s Sgt Casper, afraid to admit he’s out of his depth, leads the squad deeper into danger; attempted acts of gung-ho heroism end only in death. The men fall to infighting, mutiny, suffer mental breaks. They firebomb a Cajun trapper’s home out of frustration and kill each other in pointless law-of-the-jungle scraps.

Collapse in discipline, fragging, atrocities inflicted upon the local population - it’s not hard to see why Southern Comfort has been interpreted as ‘Nam allegory. Hill himself recognised it would be viewed that way when heading into production, firmly telling the cast before shooting began: “People are going to say this is about Vietnam. They can say whatever they want, but I don't want to hear another word about it”.

No film is created in a vacuum, of course. Hill conceived Southern Comfort in the mid-70s, not long after the last US troops had been withdrawn from Vietnam, the war having dominated domestic headlines and public discourse for more than a decade previous. Perhaps inevitably, the film echoes the then-recent conflict. Though he maintains that Southern Comfort was intended to be a universal story about men in war, Hill also concedes that the “perception of the beholder...is equally valid as the intentions of the creator”. In other words, the film can be a solid Vietnam War movie as long as the viewer chooses to read it that way.

Hill was right, though, to challenge the idea that Southern Comfort should only be interpreted as representative of one particular war. American military men march into foreign territory with imperialist arrogance, humiliating and brutalising the people there. They fire the first shots, antagonising the locals and entering a spiral of mutual destruction, realising too late that their superior firepower can only do so much in a part of the world they don’t understand. In the end, before Southern Comfort’s Peckinpah-esque final showdown, Hill’s paranoid surviving soldiers are taken in by a village of apparent friendlies - but how are they to tell these locals from the ones who want to kill them?

In 1981, this scenario would have seemed like an all-too-obvious metaphor for America’s most recent foreign intervention blunder, but there have been more of those since. The anonymous setting allows for some imagination; the film’s swamp could be Vietnam, or Cold War-era Latin America, or the Middle East now. Hill succeeded so well in making Southern Comfort not about any one conflict that it calls to mind any of America’s ill-advised forever wars, including a 20-year-long war in Central Asia that was only a couple of months ago brought to such a spectacular end. “Metaphoric without intention”is how Hill has described Southern Comfort. It’s the reason, though, that the film, in addition to being a great horror, is one that, unusually for its director, stubbornly continues to feel topical.