Backrooms Is HBO Max's #1 Movie & Proves Its Viral Horror Experiment Worked

Published Sep 30, 2026, 4:51 PM EDT Greg is a Lead TV Writer & Critic at Screen Rant with expertise in new streaming releases. He's published over 3000 articles at SR, including weekly recommendation guides and dozens of reviews on Rotten Tomatoes. He previously worked in Development at ABC Television & Lawrence Bender Productions. Greg majored in Film Production at Chapman University's Dodge College. Greg also has years of broadcast TV production experience at major networks such as NBC, TNT, and ESPN. He currently lives in Greater Boston. Backrooms remains HBO Max's #1 most-watched movie in the United States after its recent streaming debut, marking a big win for experimental horror. The 2026 psychological horror film earned a whopping $400 million at the worldwide box office based on its very modest production budget of $10 million, becoming A24's most profitable movie of the year by a long shot. What's even more impressive is that its director, Kane Parsons, created the viral "backrooms" concept when he was only 16 and made his feature debut at the age of 20. At face value, Backrooms may not seem to make much sense in terms of concrete linear storytelling. The concept rests on the use of liminal spaces with little to no human activity, which naturally creates a sense of eeriness and dread. While that idea is plausible for the internet, the biggest challenge Backrooms faced was whether it would be able to succeed in a traditional three-act structure and be limited to a clear beginning, middle, and end. With Backrooms' continued popularity on streaming, it's safe to say the horror experiment paid off. Backrooms Is HBO Max's #1 Movie In The U.S. After Its Streaming Debut Backrooms made its wide theatrical premiere back on May 29, 2026, and enjoyed an extended run in theaters, finally ending a remarkable 14-week window in early September. The momentum then quickly shifted to the streaming world on HBO Max as part of A24's exclusive deal with the prestigious platform, hitting the streamer on September 26 and instantly becoming a #1 hit in the United States. The low-budget indie horror surpassed monolithic titles like Supergirl, which by comparison flopped at the box office, making a measly $126 million against estimated production and marketing costs of $290 million. Backrooms is one of the best recent examples of the modern indie horror renaissance that has produced some of the biggest box office hits in recent years, such as Obsession, Weapons, and Longlegs. In fact, it proves that experimental horror can work for both producers and viewers, and that audiences seemingly prefer it to exhausted reboots of big-budget superhero franchises that haven't quite recovered since Avengers: Endgame. Not only will people go to see fresh new movies with strong source material on the internet, but they will also act quickly to view it at home once it hits a major streaming platform, whether it's for a rewatch or the very first time. Kane Parsons' Viral YouTube Horror Experiment Proved It Could Work As A Movie With Backrooms being more of an exhibition of an online cultural phenomenon than a tried-and-tested formulaic horror film, there was always the risk that it would not be able to translate successfully on the big screen. While Parsons perfected his Backrooms world, it was part of a larger atmospheric subgenre known as "creepypasta", which dated back to online forums as far back as 2007. Even while watching the final product that has become an undeniable success, there's still much left up for interpretation in Backrooms that may not click for all audiences, especially those unfamiliar with the viral internet concept. Nevertheless, Backrooms was still a success among critics, earning an 87% Rotten Tomatoes score and a 74% audience score. Critics generally rewarded the film for its bold originality and gripping tension. Rolling Stone called it "the carbonara of creepypasta cinema, adding savory Kubrickian elements to its source material’s heavily salted Blair Witch Project videocam style and displaying an inventiveness that makes up for any sense of derivativeness." Similarly, the LA Times wrote, "Describing "Backrooms" as a horror film doesn’t feel exactly right. It’s a surrealist painting in motion, the equivalent of staring at Salvador Dali’s wasteland of melting clocks until it makes gut-sense." On the other hand, Backrooms was criticized by moviegoers who found it to lack depth and focus before reaching a mildly satisfying end. Whether you enjoyed it or not, it's undeniable that Backrooms is one of 2026's greatest filmmaking triumphs and is well worth watching on HBO Max for its hype alone. Backrooms Release Date May 27, 2026 Runtime 110 minutes