A24's Slasher 'Onslaught' Premieres in Los Angeles Ahead of September 4 Release
A24 unveiled its slasher film Onslaught at Regal L.A. Live on August 26, 2026, with a red-carpet premiere that drew director Adam Wingard and a cast spanning action veterans, horror icons and one very recognisable face from Aliens (Deadline).
The film opens in US theatres on September 4, 2026, giving A24 a genre entry just past the summer corridor and into the early autumn slot where horror has historically played well (Deadline; A24).
Wingard directed from a screenplay by Simon Barrett, built on a story the two developed together. The pair have collaborated before, most notably on You're Next and The Guest, and Onslaught returns them to lean, high-concept genre territory. Producers on the project included Aaron Ryder, Andrew Swett, Wingard, Jeremy Platt, Alexander Black and Barrett (Deadline).
The premise is straightforward and pulpy. An army sniper living in a trailer park protects her family when a rogue squad of genetically engineered super-soldiers breaks loose from a secret military facility and descends on the desert. A24's own synopsis keeps it tight: "super soldiers break loose in the desert" (A24).
Adria Arjona leads the cast as Celeste, the sniper at the centre of the story. Alex Pereira plays The Butcher, the film's principal threat. The supporting cast is deep and deliberately mixed: Dan Stevens as Dr. Hans Kammler, Michael Biehn as Baylor, Drew Starkey as Cyrus, Reginald VelJohnson as Josiah, Eric Wareheim as Kovacks, Rebecca Hall as Hanna Kammler, Maurice Greene as Teddy, Blake Kennedy as Daisy and Jacob Scipio as Griffin (Deadline).
On the red carpet, Arjona was joined by Jason Momoa, whom she is dating. The premiere crowd also included Wingard, Starkey, Stevens, VelJohnson, Kennedy and Biehn (Deadline).
The presence of Biehn — Hicks in Aliens, Kyle Reese in The Terminator — gives the film a through-line to the military-horrior tradition it clearly draws from. Stevens, meanwhile, reteams with Wingard after their work together on The Guest, where the actor's unsettling turn helped define the film's tone. Hall, whose career spans prestige drama and genre work, adds another layer of cast depth.
Fandango lists Onslaught at an R rating and a tight 92-minute runtime, consistent with Wingard and Barrett's preference for pace over sprawl (Fandango). A24 maintains an official page for the film at a24films.com/films/onslaught (A24).
For A24, Onslaught sits in a commercial lane the distributor has explored with growing confidence — genre films designed to play to opening-weekend crowds rather than the art-house core. With its September 4 release date, the film lands ahead of the Halloween corridor but squarely in the season when audiences start reaching for darker fare.
