After almost three decades of challenging nature’s boundaries and surmounting numerous doomsday scenarios, the “Mission: Impossible” saga finally stretches believability too far with its eighth chapter, taking a fantastical leap that breaks the audience’s suspension of disbelief. However, witnessing this spectacle, especially on an IMAX screen, is a remarkable experience. The film showcases two of the most stunning set pieces, not only in this installment but perhaps in the entire franchise, leaving me grappling with my logic while savoring the pure thrill of watching Tom Cruise risk everything for my enjoyment.

“Mission: Impossible – The Final Reckoning” is a perplexing entity that leans heavily on both the worst and best instincts of its producer-star, often favoring the former. The narrative strives to unite decades of standalone tales with fan service, referencing obscure plot points. It aims for a nostalgic farewell but loses focus, forgetting that the audience was drawn to these films for the spectacle that the daring star delivered, rather than the plot.

In its exposition-heavy first half, the film sometimes feels like Cruise and director Christopher McQuarrie are misapplying lessons from later Marvel movies, requiring the audience to recall minor details from years past for lackluster resolutions. They attempt to connect characters across different franchise generations in a way that feels contrived. Despite this, the film nearly overcomes these hurdles, showcasing that when it comes to action, the duo understands their audience’s desires — if only they weren’t simultaneously chasing a climactic farewell.

Picking up two months after the events of 2023’s “Mission: Impossible – Dead Reckoning” (which Looper also reviewed), the sentient AI known as the Entity has continued to go rogue, pushing various nations to the brink of war, making leaders turn their countries into police states, and moving the entire world one step closer to nuclear Armageddon. Unfortunately, as with the prior film, the all-encompassing power of the Entity remains oddly ill-defined, never quite elaborating on the methods it’s using to make millions distrust each other — it’s something to do with the internet, apparently, but this is a stubbornly offline film, and its vagueness feels cynically deliberate to appeal to a mass audience in our genuinely polarized era. Hell, even the civil unrest we see on expository news reports is relegated to a couple of shots of peaceful protests; the end of the world never felt so anticlimactic.

And so, we spend the best part of the opening hour-and-change spinning wheels before Ethan Hunt (Tom Cruise) properly embarks on the mission to intercept Gabriel (Esai Morales) and take down the Entity, a globetrotting treasure hunt that takes him both to the skies and the depths of the ocean. That all the relevant information needed can be established in a couple of sentences within this review should probably outline why this first half can be so frustrating, striving to be a love letter to the franchise by invoking so many of its unruly corners, but likely just leaving more casual audiences wondering whether they should have rewatched “Mission: Impossible III” before this one. With the obvious exception of the “Dead Reckoning” plot, none of these ties feel particularly relevant or circumstantial, meaning that the one callback that should make fans cheer — the return of CIA analyst William Donloe (Rolf Saxon), whose career Ethan ruined all the way back in the 1996 movie — also feels labored and superfluous by the time it comes around. Rather than being a tribute to the franchise, it’s a commercial for far better earlier installments of it.

This force-fed nostalgia also comes with an unwanted side effect, likely reminding audiences that for certain earlier stretches of the franchise, Tom Cruise was more famous for being a weird Scientologist laughingstock than an action star, a persona the franchise helped rehabilitate from “Mission: Impossible – Ghost Protocol” onwards. Thanks to his trusty team of sidekicks, and Cruise’s willingness to follow in the footsteps of Buster Keaton and Jackie Chan in depicting himself making slapstick mistakes in high-stakes scenarios, Ethan Hunt was arguably the humblest iteration of such an extraordinary, death-defying character you could imagine. In “Mission: Impossible – The Final Reckoning,” however, any attempts to give this character humility have gone out the window, and the franchise makes its final pivot away from showing the strength of the IMF team as an entire unit, to depicting Ethan as a benevolent God on this Earth, insistent he’s unworthy of the responsibilities everybody wants to bestow upon him. It’s a work of unrestrained ego that gives even the most dazzling stunts an unsavory aftertaste.

And yet, in the moment, from the second Ethan embarks on a journey to a long-lost submarine, it feels almost perverse to think about anything beyond what’s unfolding onscreen. This 10-minute aquatic showstopper raises the bar for deep sea set pieces in film thanks to a ticking-clock mechanic and a confined location that only gets further submerged throughout the sequence. It ends in the most ridiculous possible way, which had various audience members around me laughing, but I couldn’t help but be taken in by it. The resolution might be a leap too far, but it was the first sign of life that Christopher McQuarrie and Cruise showed as to what makes these films tick; they’re heist movies in all but name, and it was the first time the plot remembered this was their most vital asset.

Perhaps it’s the high bar the franchise has set since McQuarrie took over the directorial reigns with 2015’s “Mission: Impossible – Rogue Nation,” but making the final mission one that keeps unnecessarily looking in the rear-view mirror to the earliest films ends up reinforcing how much better they became in the past decade. As with the recent Marvel films, it’s misplaced nostalgia for movies we’ve long since moved on from, and thinks the only way to keep building out an expansive narrative is to paper in any cracks from the past as if they were plot holes. The second half shatters disbelief to overcome this flaw, delivering two of the best set pieces in the entire saga — but what does it say about the movie that these alone struggled to silence any of my doubts, once their respective moments had passed?

“Mission: Impossible – The Final Reckoning” hits theaters on May 23.