Boom: "Oppenheimer"

I'll say this: Oppenheimer is Christopher Nolan playing to his strengths. If this filmmaker insists on maintaining the po-facedness that has defined his work since the initiation of the Dark Knight trilogy - the humour deficiency that makes Nolan movies manna for mirthless fanboys, and made such a grinding plod out of the would-be caper Tenet - far better it be turned towards a subject such as the construction of the atomic bomb. Throughout the new film, we are sporadically reacquainted with that now-familiar sensation of solemn Nolanian straining. No other filmmaker presently working within the studio system is more keen for us to take him seriously, to present as A Very Clever Boy Indeed: clever when telling a story backwards, clever about his redeployment of familiar comic-book figures, clever in venturing war movies and biopics that unfold across several timezones simultaneously. A Nolan film remains a complex equation being worked through on an IMAX-scaled blackboard by the brightest kid in the Hollywood class; Oppenheimer duly appends modules in history, politics and thermonuclear physics. (As underlined by all those social-media posts from colleagues no less keen to show off their high-minded beach reading - Kai Bird and Martin J. Sherwin's biography American Prometheus, Nolan's source here - this is that rare summer movie for which one probably ought to study.) In its wobbly first hour, during which the film can be felt straining too much, you actually get to hear Matt Damon's General Groves hyperventilate the line "This Is The Most Important Thing In The History Of The World!" If you're anything like me, you may not be able to witness such a spittle-flecked, footstomping fit of the vapours without chuckling, but - once the giggles subside - the film does much to impress upon us that J. Robert Oppenheimer's labours might legitimately be considered a matter of life and death.

One early encouraging aspect is Nolan's visible rediscovery of actors. They were front and centre in this director's early films: arguably he's never surpassed his work with Al Pacino and Robin Williams in 2002's Insomnia, when Nolan was still greenhorn enough to defer to thespian experience. In the Dark Knight era, however, the actors in Nolan films became secondary to concepts, schemas and torturous narrative designs, resulting in the total and utter capitulation of Tenet's (dearie me) "Protagonist". I have a spit-in-the-wind theory that Nolan was so spooked by the death of Heath Ledger that he thereafter backed away from anything that struck him as human, vulnerable, mortal - the qualities that made the characters in his earlier puzzle-pictures so compelling. Yet in Oppenheimer, he sears every angle of Cillian Murphy's death's-head features onto the screen, the better to allow close, near-constant study of a figure seemingly irradiated by complicity and guilt. (To the charge the movie shows us nothing of Nagasaki, Nolan responds with a wasteland of a face.) Lest that get too much - lest straining set in for good - he surrounds his lead with people you're only too glad to encounter, the cushioning good company we need so as to sit through the entirety of a three-hour lecture: Josh Hartnett, David Krumholtz and Matthew Modine as fellow physicians; Tom Conti playing Albert Einstein as a relic of more innocent times in theoretical physics, when the numbers weren't attached to death counts; Gary Oldman playing President Truman as Reg Holdsworth. Nolan works one notable miracle in getting the perennially puckish Robert Downey Jr. to act his age - or how someone his age would have presented in the mid-1950s - as Lewis Strauss, the scheming Salieri to Oppenheimer's Mozart, busy engineering his rival's downfall in the wake of WW2. Given that Nolan presumably has access to the best casting directors in all Europe, I could have done without Kenneth Branagh doing a funny accent as Niels Bohr (when he talks of physics' "sheet music", it took me a moment before I realised he wasn't cussing), and the refusal to overdub mean we lose 25% of the dialogue to Ludwig Göransson's persistent score and ominous Dolby rumbling. That's well down on Tenet's 75%, though, and what's important is that amid all of the film's huffing and puffing, we keep catching glimpses of the human cost of building bombs.

In the early stages, granted, glimpses are all Oppenheimer has to offer. We initially get thin slivers of scenes from all over the timeline, which build momentum but gather little heft; what understanding there is here - whether of human interaction or thermonuclear physics - appears stuck at a high-school level. (For an hour, it's a movie only an undergraduate could take seriously.) Having made a fortune by making movies for nerds, Nolan might have found his way to lionising history's ultimate nerd: bullied in college, this Oppenheimer buries himself in books, takes refuge in data, and eventually achieves a dominance of sorts over the very world that had tormented him so. Like a 21st century film director, he builds worlds (the film's pulse quickens the closer we get to Los Alamos) and blows shit up; in his downtime, he bunks up with Florence Pugh in the year's most laughable sex scene (one that could only have been choreographed by a nerd: "I read it in the original German" used as a pick-up line, congress halted so that one party can get a book down off a shelf), abandons her for Emily Blunt, and - as the latter succumbs to her own doubts, and subsequently hard-faced alcoholism - with Pugh again, this establishing this was a nerd who got laid a record three times. Yet what proves semi-interesting about Oppenheimer is how it comes to function as metatext; there are long stretches where it feels like Professor Nolan giving a lecture to his own admirers. His Oppenheimer is someone keen to put his skills in the service of winning a war, and yet his righteousness leaves nothing but rubble in its wake. An early, offhand attempt to assassinate his mocking mentor (injecting a Biblical apple with potassium cyanide: knowledge gone sour) doesn't come off, but Oppenheimer spends the bulk of its three hours watching its small-p protagonist destroy relationships, rivals and eventually entire Japanese cities. Whether it will be heeded remains to be seen, but there may be a warning here for those considering taking to social media to threaten physical violence against anybody threatening Nolan's chances of winning the Best Director Oscar. (Though even that prize wouldn't be vindication enough for some: in the fanboys' eyes, the great God-like Chris would merit all thirty-odd awards, including that for Best Animated Short.)

For years, these true believers have gone gaga over the logistics of each Nolan film while overlooking the work's coolly impersonal limitations and failings. But Oppenheimer is different, emerging instead as a film that sets its maker in direct, often frank conversation with his audience, and possibly even with himself. The drama reaches critical mass around the midpoint, with a second sex scene that repairs some of the damage done by the first - chiefly because the bold staging yanks us outside the Oppenheimer worldview to confront us with the film's true subject: fallout, in all its forms. It's not the only point in these 180 minutes where the prevailing cleverness - or tricksiness, which isn't quite the same thing - does add a kind of weight. When we arrive at the detonation of the plutonium bomb, Nolan stages a dramatic coup in line with the published science, withholding the sound we expect so as to put us in renewed synch with Oppenheimer's shallow sickbed breathing. When the explosion finally hits the speakers, it's less the big bang we associate with summer movies than a deathly rattle: it goes right through the physicist, shakes another decade of life from Murphy's performance, and recurs whenever the world again threatens to get too much for the character. We continue to feel its reverberations. Here, then, is consequence; here, the gravest of responsibility, the very elements that went AWOL from the multiplex over the last decade-and-a-half of Marvel movie dominance, and more so than the filmmaking, Nolan's restoration of those elements to American cinema may be Oppenheimer's most impressive aspect. Reviewing an earlier account of the Manhattan Project - Richard Rhodes's 1986 book The Making of the Atomic Bomb - Clive James noted this story boils down to "how a group of the cleverest men on Earth combined their best efforts in their belief that building a bomb to kill a hundred thousand people at a time was the only thing to do. There can be moral discussions of the modern world that don't take that fact in, but they won't be serious." Nolan is deadly serious about his subject and the implications of Oppenheimer's life and work - and, this once, that seriousness seems neither disproportionate nor misapplied.

Oppenheimer is now playing in cinemas nationwide.