Unfortunately, the first of these films is not just a commercial fiasco — it is a complete storytelling flop from top to bottom, an unbelievable lapse at understanding what interests audiences. Given all of the sacrifices Costner made to bring his vision to the big screen, it’s baffling that the end product is so bland, devoid of the spark Sheridan can conjure from “Yellowstone” and its spinoffs every week.

Lest you think this a bad-faith argument, I wanted nothing more than to be swept away by “Horizon.” Arriving at the first Thursday preview screening at my local theater in Queens, New York, there were eight other audience members sprinkled throughout the vast auditorium. They all had to be fans of Costner, “Yellowstone” or Westerns in general, given the mixed reviews and brain-churning runtime. Yet one by one the audience filtered out, leaving me the sole adventurer that stuck around for the film’s final “Coming up in Part 2” montage.

During the last hour of “Horizon,” a man sitting several rows behind me descended the steps in the dark theater, spilled his half-full bucket of popcorn midway down, reached to pick it up — but was interrupted when he let out an audible fart. At this point, he abandoned the bucket and hustled to the door. If only “Horizon” matched that level of compact storytelling and wit, featuring a memorable character facing challenging odds.

Perhaps if Costner had stuck to the following fundamentals that Sheridan has baked into the DNA of “Yellowstone,” “Horizon” wouldn’t have failed.

A proper scope of storytelling

At its core, “Yellowstone” is a simple soap opera: The Dutton family owns the biggest ranch in Montana, and they are always trying to keep their property out of the hands of greedy outsiders — even as they fight amongst themselves for control. It’s simple and effective, yet “Horizon” — hoping to be epic — seems to want to tell the story of every single person who headed out west after the Civil War, looking for fame and fortune. That results in way too many characters being introduced, and it’s difficult to latch on to anyone when you’re constantly shuffling around, meeting new people. Some of the backstories are interesting, some aren’t, and yet everyone offers long speeches about the new frontier The stories are then intertwined, creating an endless sprawl. As my colleague Owen Gleiberman noted in a column about the film, this pacing could work in a television series, but for a film to have so much homework without getting to the good stuff is a fatal flaw. After all — Costner doesn’t even show up for AN HOUR into his own epic!

The ebb and flow of great acting

For an actor as naturalistic as Costner, his direction of actors is baffling in “Horizon.” A constellation of great leads and character performers alike — Jamie Campbell Bower! Jena Malone! Jeff Fahey! Luke Wilson! — drift in and out, seemingly instructed to pick an accent and cadence on their own and just stick with it. Despite the national melting pot, the scenes recall regional performances of “Our Town,” where everyone is just trying to steal the spotlight from each other, dialect be damned. Meanwhile, the “Yellowstone” leads quickly mastered the perfect interplay with each other early on, bouncing off friends, lovers, enemies and family members with ease and acid tongues.

Craft a world that feels lived in

Outside of the gorgeous natural backdrops, the artifice of “Horizon” doesn’t allow for a moment of lived-in authenticity. Garments look fresh and never-worn, despite the hard lives of all of the characters — maybe they only buy off the rack? Brows, teeth and styling look suspiciously modern, as if this project isn’t worth day players getting a haircut for. And Costner wears the silliest looking big blue hat you’ve ever seen on the range. Meanwhile, part of the appeal of “Yellowstone” is it seems like a glimpse into the very real (if very wealthy) lives of those running massive ranches, as confirmed when I interviewed an actual ranch matriarch, who confirmed that the look matched reality.

Bringing the drama!

Outside of its overbearing score, “Horizon” is as dramatically inert as a rolling tumbleweed. Sure, a few people die and there are some shootouts, but these moments are few and far between countless scenes of character introductions. The bullets also don’t wound the audience too deeply, as, despite their endless chatter, we don’t know much about the travelers beyond their most remedial aspirations for going West: Money, a chance to start over, looking for love, etc. Meanwhile, in both his films and TV shows, Sheridan is a master of tension and release, and he knows that getting under the skin with a character in peril is a result of economical screenwriting and big stakes — both of which are missing here.

Ultimately, it’s puzzling to be presented with a passion project that feels so devoid of actual passion. With a low CinemaScore of B-, it seems Costner has an uphill battle in getting audiences to get back in the saddle again for Part 2 — let alone get the dough to finish Part 3 and get Part 4 off the ground.Maybe he should talk to the Dutton family to see if they’ll use part of their fortune to invest in the arts.