Is “The Texas Chainsaw Massacre” the greatest movie title ever? That’s the opinion of a comedian, actor and gameshow host, Patton Oswalt. A title, he tells us, “should let you see a free movie in your head.” 

The line is culled from Mr. Oswalt’s 2004 stand-up special, “No Reason to Complain,” but the bit is only nominally a joke. Tobe Hooper’s seminal horror film is the rare venture that exceeds the most elaborate of preconceptions. It’s unremitting and gnarly: Few entertainments have stuck in the craw of popular culture with as much tenacity.

On the occasion of its 50th anniversary, director Alexander O. Philippe brings us “Chain Reactions,” a cinematic meditation on a notoriously “scruffy, no-budget independent film.” Utilizing clips from “The Texas Chainsaw Massacre,” some of them previously unseen outtakes, Mr. Philippe attempts to unpack the qualities that have made it an enduring artifact. Five notables are on hand to testify about the film’s impact on their lives and careers. The broader culture and the body politic figure into it as well.

Mr. Oswalt is here, as are the directors Takashi Miike and Karyn Kusama, the Australian critic Alexandra Heller-Nicholas, and the writer Stephen King. Each of them is interviewed within the dilapidated environs of a farmhouse similar to that seen in “The Texas Chainsaw Massacre.” Director of photography Robert Muratore imbues the place with a keening golden light that is a far cry from the grain of the original movie. As is noted repeatedly during “Chain Reactions,” the picture’s coarse cinematography is an inherent component of its unsettling power.

Ms. Heller-Nicholas describes watching an umpteenth-generation dupe of “The Texas Chainsaw Massacre” and how it made the film seem Australian: its harsh yellow light bringing to mind the changes of atmosphere wrought by the continent’s dust storms. Mr. Philippe managed to track down some of those degraded prints and places them side-by-side with clips from the real thing. The commonalities between Hooper’s arthouse mainstay and Aussie favorites like “The Proposition” and “Wake in Fright” are uncanny.

“The Texas Chainsaw Massacre” was recognized as something unique upon its release. The Museum of Modern Art acquired the film for its collection straight out of the box. In a contemporaneous review, Rex Reed, a critic not always amenable to unconventional strains of cinema, hailed the film for its brilliance. Not everyone agreed: Countries around the world banned the picture and, as Mr. Oswalt notes, “a specific generation” of movie-goers weaned on old school bumps-in-the-night took a pass. Hooper’s picture drew a line in the sand.

Mr. Phillippe has made a specialty of his fascination with fantasy, science fiction, and horror films, having done deep cinematic dives into “Star Wars,” “Alien,” “The Exorcist,” the director David Lynch, and the unstoppable William Shatner. Like them, “Chain Reaction” will appeal predominantly to fans, a select group for whom the preaching to the converted is a means of confirmation and community. 

That isn’t to say “Chain Reactions” doesn’t have its share of insights into the filmmaking process, the ramifications of art, and the less attractive attributes of the human animal. Here is a film whose purview is limited but surprisingly deep.