The first third, maybe even half, of this film is a very well-executed unsettling family drama. Toni Collette leads with a very Shelly-Duvall-in-The-Shining (or even Essie Davis in The Babadook) style performance, really grounding the (natural) horrors of the film. An excellent portrayal of grief. The visceral horror of the film was well done, apart from a few clunky aspects like the cliche of actually having a teacher in a classroom outline a myth or moral that relates very directly to the store (here the Greek tragedy of Iphigenia, which was much better demonstrated in 2017’s The Killing of a Sacred Deer).
As the film shifts gears towards its third act, it becomes a lot less special and well-executed, as it starts focusing a lot more on plot instead of focused atmospheric character scenes, and as it starts piling on typical supernatural horror cliches. This mounts to an outright goofy ending, complete with insistent offscreen exposition, that really grinds down the teeth of what the film was gesturing at saying about mental illness and family patterns. A properly curdling family drama building up ideas around familial bonds and the effects of grief loses steam as it gets sucked into a genre runaround of demons, cults, twists, flashy violence, etc. The supernatural angle was introduced too explicitly and too late to really sync up with the rest of the film in any meaningful or satisfactory aesthetic or thematic sense. The onslaught of exposition really emphasises the contrivances.
What themes the film does explore, like the titular hereditary afflictions, are ugly and unbalanced in how the fall to genre truisms obscure the strength of any statements that might’ve been made. Playing into the Greek tragedy angle and proclaiming fate, hereditary illness, as inescapable is of questionable real-world power, but does make for effective horror. That kind of truism of genetic fate, becoming like one’s elders, is horrific enough of its own to sustain a film like this, especially with a cast clearly up for it. Not only literalising it, but contriving it so that ends up subservient to a plot about demons and cults (instead of keeping that a secondary genre element to build up a world to make that case) doesn’t meld neatly with the stronger first section of the film. The film is not exactly iterative; the droning atonal music, the creeping glides of the cameras, the haunted house setup, demonic apparations, even the style of the lead performance (one that was increasingly wasted as the film went on; her scene begging her partner to throw a book into the fire has nothing even to do with her arc for example), these are all horror hallmarks, arguably even just A24 hallmarks. When it focused just on realising those elements as effectively as it could, it worked well, but when it tried to push the genre aspect even further, it felt a lot more discordant. Three creepy books about demons, and a creepy old photograph, ooh.