It’s hard to overstate the impact that “The Exorcist” had in 1973. People didn’t just get scared during the movie, but rather they walked into the movie already scared. The film itself was regarded as something akin to a satanic rite, and audiences entered the theater half expecting to walk out possessed by demons.

That impact is impossible to replicate 50 years later. There have been five sequels over the years — including the new “The Exorcist: Believer,” out Friday, Oct. 6 — plus plenty of imitators, including “The Conjuring” series. Each one has dissipated the power of these images, and by now, if you’ve seen one girl projectile vomiting and twisting her head 360 degrees, you’ve seen them all.

That’s why the best parts of “The Exorcist: Believer” don’t have anything directly to do with demon possession.

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The film begins in Haiti, with a radiant, heavily pregnant woman walking around enjoying the sights. She’s joined by her husband, Victor (Leslie Odom Jr.), a photographer on an assignment, and everything seems so wonderful that it’s clear something horrible is about to happen.

This time, horrible takes the form of an earthquake and the slow, terrifying collapse of the hotel where Victor’s pregnant wife has returned to get some rest. Flash ahead 13 years. Victor is a single father of teenage Angela (Lidya Jewett). She’s the baby girl who survived the building’s collapse, while her mother did not.

这只需要几分钟,但是weird, subjective way of movies, it gives us just enough to feel invested in this family. We stay invested too, which keeps the gruesome elements from taking over and turning the film into a ridiculous festival of grossness. We like this young girl and would prefer she not have to be regurgitating buckets of tarry slime onto the ceiling.

“Believer” takes its time getting to the exorcism scenes, which is good because it indicates that the filmmakers have more up their sleeve than spectacle.Ellen Burstynreprises her role as Chris MacNeil, the mother of the possessed girl in the 1973 “The Exorcist.” Chris has since become an internationally recognized expert in demon possession.

在90年,·伯斯汀retained all her familiar force and drive to the extent that every time she appears, she risks blowing everybody else off the screen. It’s easy to believe that both demons and fellow actors would be scared of her, and perhaps for that reason — after providing some of the movie’s best moments — her character is pushed off to the side and all but vanishes.

That’s when things go downhill.

For all the movie’s modest but palpable virtues, “The Exorcist: Believer” has one problem it cannot solve: No one has come up with a new way to do an exorcism. By now, don’t you feel that you could do an exorcism yourself if the need ever arises? All you need is a cross, a Bible, a few incantations that order the demon to leave, and you have to be prepared to get thrown into a wall two or three times over the course of the night.

Here, five decades later, all the usual elements are present: the growling voice, the profanity, the demon makeup straight out of the original film, the head twisting around. The only thing that’s new in “Believer” is that there’s now two girls possessed instead of one. But even then, they’re not doing anything different from each other. According to the medical monitors that the girls are unaccountably hooked up to, they even have the same heart rate and blood pressure.

A double exorcism isn’t double the fun. It’s one exorcism with two heads.

None of this bodes well for the supposedly rebooted franchise. There’s reportedly another entry coming in 2025, “The Exorcist: Deceiver,” but what will they do for that one? Have three possessed girls?

Until someone is able to come up with a new way to depict possession or the battling of possession, this franchise is going nowhere.

Correction:An earlier version of this story misspelled actor Olivia O’Neill’s name in a photo caption.

Reach Mick LaSalle: mlasalle@sfchronicle.com