It is time we start taking comic book movies seriously. When the first Iron Man came out 10 years ago—a few months before The Dark Knight—it was seen as “great for a comic book movie.” Since then, the Marvel Cinematic Universe (MCU) has dominated the summer blockbuster season, to the point that their most influential idea, a shared universe, has infected popular entertainment as we know it.

Avengers: Infinity War is the latest comic book movie, and it arrives with the hype and expectation of “the biggest crossover in history.” Not the biggest comic book crossover, but the biggest crossover, period. The grim irony is this film cheapens everything that made the MCU so special. Fans will feel cheated, like the movie spit in their eye, and it may take some serious soul-searching to figure out why that is.

There are so many characters in Infinity War—at least two dozen superheros from previous films—that summarizing the film is basically pointless. The biggest challenge facing screenwriters Christopher Markus and Stephen McFeely, along with directors Anthony and Joe Russo, is that there are so many characters it’s difficult to make sure they all get their due. Their solution is to make several mini-sequels and paste them together.

In Infinity War, there are inelegant parts of Guardians of the Galaxy, Thor, Doctor Strange, Captain America, Black Panther, and Spider-Man: Homecoming. Most of the time the heroes spend time apart, in strange configurations. Thor (Chris Hemsworth), for example, somehow teams up with Rocket (Bradley Cooper) and Groot (Vin Diesel). Sometimes these configurations are meant for laughs, but most of the time it is just tricky to keep everyone straight. You know how the last season of Game of Thrones felt rushed, to the point where everyone’s plan hung together awkwardly? Infinity War is like that, except with the added complication that it takes place on several planets.

The thread uniting all these heroes is the villain. Josh Brolin plays Thanos, a genocidal maniac whose idea of “balance” is to destroy half of all life in the universe. Thanos gets the plurality of screen time, and multiple opportunities to explain himself. Unlike the villain in Black Panther, whose ideas were rooted in history and were so forceful they were almost convincing, Thanos’ thirst for power amounts to little more than a default antagonist. Brolin tries to bring some soul into the performance—including a flashback that shows his kinder side—yet his motivations remain murky. In point of fact, what should be the movie’s most emotional moment includes a character whose sole purpose is to explain what Thanos is feeling. This is a classic example of why movies should always show, never tell, and it does not help that Thanos looks like what would happen if you wrapped a rubber band around a wrinkly ballsack.

The first Avengers film and its sequel, Age of Ultron, had the benefit of Joss Whedon’s leadership. He is not an intuitive action director, but he has an ear for dialogue. At their best, his Avengers films functioned as character-driven comedies punctuated by moments of exaggerated action, or explosions. The Russo brothers have seemingly nothing unique about their directing style; they are Company Men to the core, adhering to the Marvel aesthetic of flat colors and little depth. All of the Avengers films end with dull automatons rushing toward the good guys, giving them opportunities to show off their skills. If the Marvel Cinematic Universe aims to rise above its source material—and reshape popular entertainment—it needs to move beyond climax after climax with unremarkable, repetitive violence.

The best Marvel films, Captain America: The First Avenger and Black Panther, are about one simple question: What does it mean to be good? Chris Evans and Chadwick Boseman are intuitive actors, doing better work than their roles require, so they found a moral core that made the case for why superhero films should be taken seriously. Simple lines like “I don’t like bullies,” or “Wakanda forever” crystallize our need for leadership, our yearning to believe in someone else, our hope that we will all be OK. Infinity War does not seem to grasp this appeal. It is full of quips, with some jokes landing better than others, but the heroes are stretched too thin to have personalities, let alone values. Now Robert Downey Jr.—a man who owes his reborn career to Marvel—cannot hide that he looks bored and desperate.

Despite its missteps—including an audience-dulling opening act from which it cannot quite recover—there are some shiny spots on what amounts to a highlight reel of a better, more coherent film. As Dr. Strange, Benedict Cumberbatch has some fun knocking down Iron Man a peg or two. Elizabeth Olsen plays Scarlet Witch, and she finds convincing emotional reserves in a scene that we have seen dozens of times before. (That being said, her Eastern European accent from Age of Ultron inexplicably disappeared.) There are callbacks to earlier MCU films that you may not suspect, and Thor’s arc leads to the sole instance where Infinity War resembles glossy, gorgeous pop art.

But for each transcendent moment, there are dozens more where we see actors go through the motions of their contractual obligations. A picture of Chadwick Boseman recently went viral because the actor looked so unhappy at the Infinity War premiere. Anyone who sees the film will totally get the feeling.

It is difficult to discuss Infinity War without acknowledging its dark tone and the implication of its ending. Whether they are happy or sad, the best endings have an inevitability to them, as well as a concurrent emotional payoff. Infinity War ’s certainly feels inevitable, minus all the emotion. It goes through the motions of darkness, in a perfunctory way that hardly seems final. It’s such a misfire, borne out of cynicism and a dearth of imagination, that Infinity War undermines the films that precede it (Black Panther in particular). For more than a decade, the Marvel films have varied in quality, so they either felt like two steps forward and one step back, or one step forward and two steps back. Avengers: Infinity War does not step backward. It leaps backward.

Avengers: Infinity War opens Friday in theaters everywhere.