Originally Published: 20 JUL 23 09:22 ET

Review by Brian Lowry, CNN

(CNN) — “Oppenheimer” seeks to match the mythological nature of its central theme – an “American Prometheus,” punished for bringing humankind the seeds of its potential destruction – with a movie of equal heft, scale and (most of all) length. Writer-director Christopher Nolan’s epic film essentially consists of three chapters, with the middle, Atlas-like, holding up the weaker, drawn-out beginning and end.

In a way, this biography of Robert Oppenheimer, who came to be known as “the father of the atomic bomb,” serves as a sort-of World War II bookend for Nolan, along with “Dunkirk,” around his jumbled “Tenet.” Yet where “Dunkirk” possessed crisp economy, “Oppenheimer” sprawls out with a giant cast and back-and-forth structure that takes some time to settle in, and even then will likely leave many viewers rushing to Google to flesh out its details.

That’s not necessarily a bad thing, and concerns about the latest war in Europe involving a nuclear power feed an unsettling “The past is prologue” sensation watching the movie, made more sobering by its protagonist’s naive hope that nuclear deterrence will make war “unthinkable.”

Still, Nolan juggles a lot, in a way that somewhat works to the movie’s detriment. The excellent midsection proves fascinating, in which Oppenheimer (Cillian Murphy) guides scientists and the military in a desperate race to catch the Nazis – told, rightly, that he has become as much a politician and salesman as a physicist.

By contrast, the film sags a bit during both his pre-war years and post-Hiroshima regrets. At the least, some judicious editing could have curbed the three-hour running time without sacrificing (indeed, perhaps enhancing) its impact. And while there’s power in artfully presenting how devastating the bomb was, “Oppenheimer” surprisingly spares us from the grisly aftermath of the Japanese cities targeted. (Nolan has explained that’s because the movie unfolds principally from its namesake’s point of view.)

The key device filters this sweeping history through a Cold War era hearing meant to determine if Oppenheimer should have his security clearance denied, retaliation for his outspokenness about nuclear policy. His persecutors exercise leverage based on his pre-war associations with communists, among them his relationship with the alluring and troubled psychiatrist Jean Tatlock (Florence Pugh).

A Nolan favorite featured in several of his films, Murphy delivers a career-topping performance. Oppenheimer became haunted by the morality of what he had midwifed, and his messy personal life and affairs coexisted with his beautiful mind – a duality the actor conveys in a way that overshadows the bigger names in supporting roles.

Of those, Matt Damon stands out as General Leslie Groves Jr., tasked with overseeing the Manhattan Project; Emily Blunt as Oppenheimer’s wife, Kitty; and Robert Downey Jr. as Lewis Strauss, a founder of the U.S. Atomic Energy Commission, who pointedly observes regarding Oppenheimer, “Genius is no guarantee of wisdom.”

As for the smaller additions, they gaudily include Kenneth Branagh, Rami Malek and another alumnus of Nolan’s Batman trilogy, Gary Oldman, in a cameo as Harry Truman that, with “Darkest Hour,” puts him one performance as Stalin away from an Allied leaders hat trick.

With its everyone-and-the-kitchen-sink casting, alternating between color and black and white, fit-for-Imax spectacle and Ludwig Göransson’s pounding musical score, “Oppenheimer” seeks to overwhelm the audience, an approach that works to an extent. There’s also an audacity simply in releasing such a serious film in the midst of summer, a time traditionally associated with lighter fare and sequels – never mind that several of them have face-planted theatrically.

Still, the anticipation surrounding the movie (from Nolan devotees to the arbitrary “Barbenheimer” double-feature joke turned marketing hook) feels disproportionate to the merits of what is, finally, a good movie, but not some sort of cinematic event.

Even before Covid began Nolan served as a champion for the theatrical experience, a campaign that carried through his efforts to get “Tenet” released. That process landed “Oppenheimer” at a new studio, Universal, after a long affiliation with Warner Bros. (like CNN, a unit of Warner Bros. Discovery).

“Oppenheimer” is well worth seeing, now or later. But if that viewing doesn’t come in a movie theater, at least that won’t be the end of the world.

“Oppenheimer” premieres July 21 in US theaters. It’s rated R.