As a movie-watcher develops a more clearly honed sense of their own taste, they may come to understand certain disparaging critical remarks as covert positives. A connoisseur of gore might hear a new release knocked as “gratuitously violent,” for instance, and prick up their ears in the knowledge that they’re in for a treat. Those with formalist leanings, privileging aesthetics over narrative, will take the disses “more like a feature-length music video” or “90-minute perfume commercial” as compliments. Personally, when a horror film gets dinged on the grounds of being “overlong” or “full of bizarre tangents that go nowhere”, I take notice and pay attention. The unwieldy, the inexplicable, the ambitious-to-a-fault – this is my cinematic happy place.

Midsommar director Ari Aster: 'I often cling to dead things' Read more

That particular stance has made this summer’s gradual rollout of Ari Aster’s new folktale-nightmare Midsommar something of a line-in-the-sand moment for this critic. Clocking in at a whopping two hours and 20 minutes (a far cry from Aster’s initial assembly cut of three hours and 40 minutes, to keep everything in perspective), it immediately lifted eyebrows as the sort of big swing from a rising indie auteur establishing himself as a key voice. Just about everyone agreed that Aster’s got an audacity to his method. Whether that enriches or detracts from his films remains a topic of some debate.

Time’s Stephanie Zacharek described Aster as “obsessed with building tension to the point of losing the plot” in her mixed review. New York magazine’s David Edelstein said: “Aster paces Midsommar more like an opera (Wagner, not Puccini) than a scare picture,” but the director does not quite “get away with his longueurs”. The Wrap’s Candice Frederick put it more plainly, clocking the Aster’s latest as “just about the coldest – and most puzzling – film to be released this year so far.” (She even used the O-word, invoking the dreaded “overlong”.) From a handful of colleagues, I have heard post-screening lobby chatter along the lines of “It’s fine, but it doesn’t need to be 140 minutes”.

Which may not be untrue, strictly speaking. A few things happen for no apparent reason in Midsommar, their presence in the finished product confounding understanding rather than helping it along. One character with an indelibly deformed face took a prominent placement in advertising, despite only hovering around the margins of the film. In theory, there’s a shorter cut of Midsommar buried somewhere in there, a truncated edit in which everything not immediately essential to the plot’s advancement has been pruned. But god, who would want it?

There’s a bit of unspoken industry wisdom that horror, comedy and other so-called “genre pictures” are best served by a brief runtime, usually topping out at 90 minutes and seldom exceeding 100. I prefer Roger Ebert’s old maxim that no good movie is too long and no bad movie is short enough. When a viewer has tapped into a director’s frequency, there’s a willingness to follow where the script leads, at which point strangeness and confusion become alluring rather than alienating qualities.

Facebook Twitter Pinterest Mia Goth in A Cure for Wellness. Photograph: Allstar/20TH CENTURY FOX

The odd ends jutting out of a work’s central story make for its most fascinating, and in the case of horror, their enigmatic quality renders them all the more frightening. To go directly for the most unimpeachable example, where would The Shining (146 minutes) be without the dog mask fellatio or the putrefying tub woman? More recently, Gore Verbinski’s A Cure for Wellness (also 146 minutes) took an extended detour to watch in stilled awe as Mia Goth danced with some dirtbag at a Swiss bar. South Korean export The Wailing (156 minutes) piles on self-contained displays of cinematic might until the audience feels like they’re holding on for dear life. Each selection could function without the scenes in question. To be extraneous, however, is not tantamount to being dead weight.

We’re afraid of what we don’t understand – this is one of horror’s operating principles. The frights that elude comprehension stick with us the longest, if for no other reason than our need to make sense of them. There’s certainly virtue in economy, in knowing which deposits of fat need trimming and which will keep everything nice and flavorful. That should still leave room for shagginess, the instinct to wander through obscure back alleys of imagination regardless of their superficial relevance. The power to generate fear proves them relevant, as a potent part of the whole. In one sense, Midsommar is about the terror of going to an unfamiliar and unfathomable place, where the laws of physics have been all but overturned. The unease that the American tourists feel while visiting a Swedish commune with a sinister secret mirrors that of the audience; everyone’s just scared of not knowing what the hell is going on.