A documentary directed by David Kittredge. Unrated. 112 minutes. Screening at the Boston Underground Film Festival.

My friend Bilge Ebiri likes to say that everybody has at least one John Boorman movie they love unreservedly. The first that comes to mind for me is “Point Blank,” the director’s 1967 psychedelic noir starring Lee Marvin as an avenging angel of death in a hyper-stylized San Francisco dreamscape that plays like “The Terminator” as directed by Alain Resnais. But I also adore “Deliverance,” his terrifying exploration of masculine helplessness in a forest primaeval, as well as “Hell in the Pacific,” which had Marvin and Toshiro Mifune fighting WWII mano-a-mano on a deserted island. Other Boorman films beloved by many include “Hope and Glory,” “Excalibur,” “The Emerald Forest,” and I even know a few hearty souls who will make a case for “Zardoz,” a nutzoid futuristic mind-bender starring Sean Connery as a sexy savage in a mankini. (The movie is indeed better than its reputation, though attempts to reclaim it as a masterpiece strike me as a tad overzealous.)

Just about the only Boorman movie you don’t see anyone going to bat for is “Exorcist II: The Heretic.” A legendary fiasco, the director’s ambitious 1977 follow-up to William Friedkin’s hair-raising cultural phenomenon is one of the most hated of all sequels, famously laughed off the screen at a Pasadena preview where Warner Bros. executives were said to be chased out of the theater and into the street by angry patrons. (Bless his heart, Hurricane Billy never tired of telling that story.) But the drama behind this allegedly cursed production is even wilder than what ended up onscreen. Making the movie almost killed Boorman, and then it almost killed his career.

Director David Kittredge’s sympathetic and engrossing documentary “Boorman and the Devil” attempts to set the record straight and reposition “The Heretic” alongside other ill-starred, budget-busting boondoggles like Friedkin’s “Sorcerer,” Martin Scorsese’s “New York, New York,” Peter Bogdanovich’s “At Long Last Love” and Michael Cimino’s “Heaven’s Gate.” The movie convincingly argues that “Exorcist II” was not a mere failed franchise cash-in, but rather one of those grandiosely intentioned, exorbitantly expensive, late-1970s Icarus flights where an auteur high on his own supply steered too close to the sun.

The doc is catnip for film buffs, especially us aficionados of the “Easy Riders, Raging Bulls” era when the lunatics were briefly placed in charge of the asylum. Director Kittredge has assembled some wonderful interview subjects, including the now 93-year-old Boorman -- photographed in his Irish home in front of a “Zardoz” mask with the sword from “Excalibur” by his side – as well as a dirt-dishing Louise Fletcher and a hilariously over-it Linda Blair. Putting this all into historical context are a murderer’s row of film scholars like my buddy Bilge, biographer Joseph McBride, the great critic Stephanie Zacharek and my old pal Simon Abrams, who I’m a little disappointed to see did not wear his “Zardoz” belt buckle to the shoot.

I think the biggest problem was that John Boorman just didn’t like “The Exorcist.” He passed on the first picture before it was offered to Friedkin and only agreed to make a sequel if he were allowed to do something entirely different. His friend Stanley Kubrick told him he should just make the same movie again with more blood and guts. Instead, Boorman’s idea was “not a sequel, but a riposte.” Nearly every creative decision in the making of “The Heretic” was a direct rebuke of “The Exorcist” – replacing Friedkin’s gritty, documentary-style grounding with a lush soundstage artifice while countering the first film’s traumatic shock effects with dreamy metaphysical noodling. Boorman wanted to make a movie about goodness and healing, but never seemed to consider that following up one of the most popular films of all time with its polar opposite might itself be considered heresy.

“Boorman and the Devil” is one of the best movies I’ve seen about the making of a movie, respecting the artists’ intentions without being afraid to spill some seriously unflattering behind the scenes stories. The candor of all involved reminded me more than once of reporter Julie Salamon’s book “The Devil’s Candy,” in which an all-access account of making Brian De Palma’s “The Bonfire of the Vanities” turned into an autopsy of a disaster. Like “Bonfire,” “The Heretic” is an extravagant visual wonder built atop a foundation that was never going to hold. The doc’s exploration of the in-camera special effects Boorman borrowed from early silent cinema are magnificent, as was the filmmaker’s attempt to build an Ethiopian mountaintop in a Burbank studio. But it turned out the dirt they had flown in and blown around the set contained dangerous microbes that put the director in the hospital after he inhaled them, shutting down production for five weeks while he almost died. There’s a metaphor in there somewhere.

Speaking of dirt, there’s plenty to go around from the principals. Blair’s still-seething disdain for screenwriter Rospo Pallenberg is especially funny, as is Fletcher’s stern disapproval of the teenage actress’ habitual tardiness. But the worst of it concerns a certain repeat ex-husband of Elizabeth Taylor, who at the time of the shoot was putting away three bottles of booze a day. Boorman wanted his “Deliverance” star Jon Voight for the lead role of a conflicted priest investigating the events of the previous picture. Instead, he wound up with Richard Burton, whose woozy affect and epic pronunciation of the word “evil” as if it were a town called “Eeville” tip even the most straightforward dialogue scenes into camp. Boorman’s lifelong friendship with Lee Marvin may have made him overconfident when it came to wrangling drunks, but in hindsight the director diplomatically concedes that Burton’s performance was “limited.”

“Boorman and the Devil” doesn’t make an argument for “The Heretic” so much as it argues for movies like “The Heretic.” We need these kind of grand follies and swings for the fences, even if they don’t connect. Especially now that Hollywood executives prefer algorithmic regurgitation and rigid franchise maintenance, it’s unthinkable to imagine a sequel as grandly ambitious and deeply fucking weird as “Exorcist II” getting made today. Kittredge’s documentary inspired me to give it another look. And while I still think the movie pretty much stinks, it’s a hell of a lot more interesting than “The Exorcist: Believer.”

“Boorman and the Devil” screens at the Brattle Theatre this Saturday as part of the Boston Underground Film Festival and “Exorcist II: The Heretic” screens at the Coolidge Corner Theatre on Friday and Saturday night.