The film, which just had its world premiere at the SXSW Film Festival, certainly dabbles in exploitation, happily indulging every lusty 16mm frame we see of the movie within the movie, but to write it off as merely those baser elements would miss the more intriguing ideas in its first two (superior) acts. Essentially posited on the conceit of “Debbie Does Dallas… and then has an existential crisis about her own mortality,” X is an intentionally jarring experiment that mashes up tones and styles. While it doesn’t always pay off, the exercise yields curious results. The premise is as straightforward as horror movies can get. A group of filmmakers—some veterans of the burgeoning smut industry and others students from the University of Austin looking for real world experience—leave Houston on a sunny summer day in 1979 to shoot an adult film. The cinephile nerd RJ (Owen Campbell) says it’s to make “the first really good dirty movie,” but his sheltered girlfriend Lorraine (Jenna Ortega) has her doubts. The rest of the cast and crew have no such illusions, including the star Maxine (Mia Goth). Despite being the lead performer in “The Farmer’s Daughters,” and the one with the “it” factor, Maxine’s a woman who always looks like she’s crying, even when smiling ear to ear. And she’s taking this job, which carries her away from the familiarity of a strip club, because her dubious producer Wayne (Martin Henderson) promises this will be the porno that makes her a true star, as big as anyone in California—maybe even Lynda Carter! Meanwhile Bobby-Lynne (Brittany Snow) and Jackson Hole (Scott Mescudi, aka Kid Cudi) appear game for any sort of adventure. It’s a setup as old as the proto-‘70s slasher movies X emulates, but the way West approaches the material is what gives the film a bitter heart. In his best horror movie to date, The House of the Devil (2009), West similarly explored religious horror not only in a period setting, but in what felt like authentic ‘70s period filmmaking. He’s a storyteller with a real affection for slow burning tension and the anxiety which can occur before anything grotesque actually happens. With its slasher roots, X moves a little faster to the gore and other forms of visual titillation, but the filmmaker still imbues X with a deliberate patience that both builds the dread… and also the romance of its era. Indeed, the movie very much feels like a love letter to independent ‘70s cinema, even at its junkiest. Instead of being a successor to grindhouse sensibilities, it’s an ode to them. Nonetheless, the horror for much of its first hour works by relying on tense editing by West and David Kashevaroff, which withholds its most horrible images until you least expect them. This exercise in style, and freaky smash cut juxtapositions, creates an effective mood that leaves viewers always ill at ease. If only X could sustain that feeling for its full 105-minute running time. For while the film shows a surprising sensitivity toward its sex working protagonists, the depiction of the film’s proverbial monsters—the senior citizens Howard (Stephen Ere) and Pearl—is where the movie descends into the leering sleaziness of a creature feature that would’ve played at drive-ins on the seedier side of town in ’79. By design, audiences are asked to second-guess their own prejudices toward seniors, especially in a culture that both fetishizes and enviously punishes young flesh. Yet much of the last third of X relies on shock value and gross out gags at the expense of withered makeup on Goth’s face and body, and the effect never really pays off. Goth is still doubly effective in both roles. The casting obviously leans into the duality of the beauty-age paradigm, but it’s Goth’s embittered performance as both women that adds texture to the idea, and gets beyond the fright makeup she has to act through in the latter role. As an actress who’s always looked a bit like a porcelain doll ready to crack in previous movies, Goth reveals sharp edges in those cracks that’ll cut to the bone. Ortega also does solid work at cementing her scream queen bona fides in only a handful of months. Even so, the way it visualizes longing, whether in your youth or twilight, is where the horror of X thrives. That chill lives not in grisly murder set pieces, but moments like when Snow’s Bobby-Lynne sings an acoustic cover of Fleetwood Mac’s “Landslide,” and we see lyrics about aging given new teeth in the juxtaposition of Maxine and Pearl—generations at odds, even as the younger one itself is now from a bygone age. Realizing desire and regret are two sides of the same ephemeral coin that we’re all currently spending really can be the stuff of nightmares. X premiered at the SXSW Film Festival on March 13 and opens nationwide on March 18.