Somewhere out there in the vast reaches of the unknown, there is a multiplex of the multiverse, playing all the great and near-great movies that never came to be within our humble reality. (I, for one, am prepared to buy an opening night ticket for the version of The Silence of the Lambs directed by and starring Gene Hackman.) Surely one of the screens is devoted full-time to the nineteen-seventies sci-fi epic that serves as the focus of the new documentary Jodorowsky’s Dune. The Chilean director Alejandro Jodorowsky was coming of the dual cult successes of El Topo and The Holy Mountain in the mid-seventies when he decided his next project would be an adaptation of the Frank Herbert novel, first published around ten years earlier, that told the story of intergalactic maneuvering for control of a spice called melange, the life-prolonging fossil fuel of a vividly imagined star-spanning realm. Jodorowsky hadn’t actually read the book when he settled on making a film of it, but no matter. There were raging rivers of wild inspiration to ride.

In bringing the story of the unmade story to the screen, Jodorowsky’s Dune director Frank Pavich meticulously tracks through the long, unwieldy process of taking cinematic inclination to the cusp of manifest realization. Relying heavily on the recollections of Jodorowsky himself, the film revels in the joy of unabashed creation. Some forty years after the fact, Jodorowsky remains an enthusiastic advocate of everything the film could have been, joyous recounting bizarre casting coups (including key roles for Orson Welles and Salvador Dalí) and geniuses of design who were brought aboard to work on different concepts (H.R. Giger, renowned science fiction illustrator Chris Foss, and comics artist Moebius among them). He doesn’t necessarily fully convince that the film would have been an artistic triumph–the complexities of the plot could fell just about any film director, as David Lynch can attest–but it surely would have been memorable, at least if half of what Jodorowsky had in mind somehow transferred from his brain to the celluloid. Unfortunately, he also couldn’t sell the film’s full potential to the studio, all of whom balked at the estimated $25 million budget, no matter the undeniably impressive nature of the weighty concept book Jodorowsky and his cohorts delivered to them.

This cinematic “what if” exercise is enjoyable, even if Pavich never quite manages to extract greater meaning from it all. He tries to speculate that if this take on Dune had been made, it would have beat Star Wars to the screen, therefore shaping the future of blockbuster moviemaking as decisively as Lucas’s hit. It’s a fun notion to play with, but it entirely ignores the full cavalcade of factors that made Star Wars into a sensation, including the easily discernible story. It’s hard to imagine that kids would have been clamoring for action figures designed to look like Dalí in outer space emperor robes or that parents would have willingly put the “Box of Appendages” playset under the Christmas tree. The long reach of some of the visual ideas is more compelling, with many of the players Jodorowsky assembled going on to work on other productions and naturally taking the best unused material with them, but even that is more of a curiosity than the indelible thumbprint on big American movies that Pavich posits. It’s maybe inevitable that Jodorowsky’s Dune has to settle on a fairly soft conclusion. That’s a natural result when examining a phantom, no matter how sensational.