SPOILER ALERT: The following review contains mild spoilers for “Star Wars: The Last Jedi.”

Surely, all “Star Wars” fans hope each new installment will be the best ever. But in the case of “Star Wars: The Last Jedi,” that seemed like an actual possibility. Written and directed by Rian Johnson, a Sundance alum who established his serious-filmmaker bona fides with his 2005 indie debut, “Brick,” before graduating to young Christopher Nolan territory via the relatively big-budget sci-fi movie “Looper,” Episode VIII seemed to have everything going for it.

To the extent that “The Force Awakens” was essentially a heightened reboot of “A New Hope,” recycling many of the 1977 original’s thrills in fresh form with a mostly new cast, this latest chapter was positioned as the new trilogy’s “The Empire Strikes Back” — which is to say, a darker, more serious chapter (commonly regarded as the series’ best) that deepens the underlying mythology, shapes its emerging hero (originally Luke Skywalker, now Daisy Ridley’s Force-strong Rey), sets up an epic cliff-hanger and introduces a few big twists into the equation, including a whopping paternity surprise.

As it turns out, although “The Last Jedi” meets a relatively high standard for franchise filmmaking, Johnson’s effort is ultimately a disappointment. If anything, it demonstrates just how effective supervising producer Kathleen Kennedy and the forces that oversee this now Disney-owned property are at molding their individual directors’ visions into supporting a unified corporate aesthetic — a process that chewed up and spat out helmers such as Colin Trevorrow, Gareth Edwards, Phil Lord and Christopher Miller. But Johnson was either strong enough or weak enough to adapt to such pressures, and the result is the longest and least essential chapter in the series.

That doesn’t mean it’s not entertaining. Rather, despite the success of “The Last Jedi” at supplying jaw-dropping visuals and a hall-of-fame-worthy lightsaber battle, audiences could presumably skip this film and show up for Episode IX without experiencing the slightest confusion as to what happened in the interim. It’s as if Johnson’s assignment was to extend the franchise without changing anything fundamental, which is closer to the way classic television and vintage James Bond movies operate than anything George Lucas ever served up.

Say what you will about Lucas’ clunky, uneven prequels, but they covered a ton of story ground. By contrast, “The Last Jedi” opens and closes with scenes of Resistance bases under siege, in between which the movie’s central concern is the dwindling fuel level on a carrier ship under slow-motion pursuit by Supreme Leader Snoke (Andy Serkis, who for the first time in his career probably would have been just as effective playing the character without the benefit of motion capture). Even more than last summer’s “Dunkirk,” this movie is about the honor and sacrifice of a successful retreat, which isn’t nearly as dramatic as an underdog offensive.

Following the destruction of the evil First Order’s Starkiller Base, and with Mark Hamill’s Luke Skywalker in self-imposed retirement in “the most unfindable place in the galaxy,” the Resistance is spearheaded by Princess Leia, played by the late Carrie Fisher, whose entire performance is overshadowed by the actress’s premature death (she should be a figure of empowering female leadership, not tragedy). Rest assured, there is a lot of Leia in “The Last Jedi.” In fact, in a franchise that has always been progressive about representation, the women basically run the show this time around, which is arguably the best thing about a movie that introduces a purple-coiffed Laura Dern as the endangered ship’s No. 2 in command, Vice Admiral Amilyn Holdo, and save-the-day sisters Paige (Veronica Ngo) and Rose Tico (Kelly Marie Tran), who each get significant moments to shine.

Meanwhile, Rey remains the character most likely to carry on the Jedi tradition, having piloted the Millennium Falcon to the remote island where Luke is hiding, although he proves a far more reluctant teacher than Yoda ever was. (Skip the rest of this paragraph if you haven’t seen the film: The green guy makes an appearance here, surprising once again with the extent of his abilities, and from the looks of it, Johnson — or someone at a very high level — successfully made the case to go back to a practical Yoda puppet consistent with the original trilogy, as opposed to the smoother but somehow phonier-looking CG version featured in the prequels. In another nostalgic touch, this film was actually shot on film, rather than digital cameras.)

Revealed as a bearded and cloaked recluse at the end of “The Force Awakens,” Luke is funnier than we’ve ever seen him — a personality change that betrays how “Star Wars” has been influenced by industry trends. Though the series has always been self-aware enough to crack jokes, it now gives in to the same winking self-parody that is poisoning other franchises of late, from the Marvel movies to “Pirates of the Caribbean.” But it begs the question: If movies can’t take themselves seriously, why should audiences?

Harrison Ford was a good enough actor, and Han Solo an aloof enough character, that he could get away with it, but here, the laughs feel forced — as does the appearance of cuddly critters on each new planet. Both are reminders that the canonical “Star Wars” movies (as compared with last year’s adult-targeted stand-alone, “Rogue One”) must also appeal to very young children, for whom this can be a formative moviegoing experience — which is the kind of strategic thinking that previously brought Ewoks and Gungans into this universe. But do those audiences have bladders big enough to sit through a talky two-and-a-half-hour tug-of-war between the light and dark sides of the Force?

Because that is in essence what “The Last Jedi” is about: If Kylo Ren (Adam Driver) and Rey are the two humans with sufficient supernatural abilities to carry on the waning Jedi religion, which side will each of them choose? We already know who Ren’s parents are (Han Solo and Leia), but what about Rey’s? “The Force Awakens” introduced a new villain in Snoke, who seemed all the more mysterious in that he loomed over Sith apprentice Ren in hologram form. Now we see him “in the flesh” (technically CG), and he’s repulsive to look at — like accidentally walking in on one of your grandparents au naturel — but not especially fear-inducing, in part because we learn so little about him or his powers.

Ren makes a much better villain, as does Domhnall Gleeson’s Gen. Hux (though he too often serves as the butt of the script’s jokes), and together, they do more to terrorize Leia’s fuel-starved carrier than Snoke does. As was the case with the young Anakin Skywalker, Ren embodies a mix of ambition and unbridled rage, though Driver makes all that wild energy all the more unpredictable. His is one of the movie’s most challenging and effective performances, and though the internet will distract itself with a moment in which he briefly appears shirtless, it’s gratifying to see such a gifted actor in the part.

On-screen, the First Order’s army vastly outnumbers the embattled Resistance, but for purposes of dramatic identification, Johnson provides real character detail for the good guys, even the minor ones, and their losses therefore register with greater impact than in previous movies (when, say, Luke’s fellow pilots anonymously died alongside him). The mission here is merely survival, although the tension would be greater if Snoke were doing something other than space-tailgating the Resistance for most of the movie, picking off their smaller ships as they run out of fuel. In theory, what’s at stake here is the very future of the Jedi faith (which is explicitly identified as a “religion” here). It’s kind of a big deal to suggest that the belief system upon which Lucas’ entire franchise was built could fade away entirely, unless someone new comes along to uphold it, or that its chief disciple, Luke Skywalker, is now actively campaigning for its demise.

While Rey wrestles with that issue, fighters like hotshot pilot Poe Dameron (Oscar Isaac) and stormtrooper-turned-anti-First-Order-terrorist Finn (John Boyega) prove invaluable to the cause — even if their mission, which involves an elaborate detour to a swanky casino planet, doesn’t supply quite as much excitement as it ought to. While there, Finn and Rose present the movie’s political agenda, which disapproves of arms trafficking, regardless of which side the gunrunners are serving, and argues for the respect of all creatures (who should not be eaten, abused or raced for sport, but instead collected wherever fine toys are sold). They also pick up a stuttering codebreaker (Benicio Del Toro, bursting with personality) who fills this movie’s Lando Calrissian spot — for those keeping track of all the ways the film honors or inverts elements from “The Empire Strikes Back.”

It may sound like a backhanded compliment, but with so much on the line, Johnson deserves credit for not messing things up. By contrast, Lucas got himself into trouble for not catering enough to fans with his early-2000s prequel trilogy, a situation J.J. Abrams (who serves as an executive producer here) addressed in “The Force Awakens,” which felt like a thrilling, big-budget “Star Wars” fan film.

“The Last Jedi” possesses the same reverence for the galaxy Lucas created, paying homage in all the right places (from the chills we get from John Williams’ iconic fanfare to the new-and-improved walkers that appear during the climactic siege) while barely advancing the narrative. Ultimately, there’s only so much wiggle room Johnson has to play with a property that seems destined to generate a new installment/spinoff every year until we die — which means that however many Death Stars or Sith Lords the Resistance manages to defeat, there will always be more, and no matter how few Jedi remain, there can never be none.