Cillian Murphy in Oppenheimer. Photo Credit: Universal Pictures

If you’re planning on seeing Oppenheimer, prepare to leave the theater speechless.

That’s the effect that director Christopher Nolan says the film — which tells the story of J. Robert Oppenheimer, father of the atomic bomb — has had on early viewers so far.

“Some people leave the movie absolutely devastated. They can’t speak,” Nolan told Wired in their latest cover story.

“I mean, there’s an element of fear that’s there in the history and there in the underpinnings. But the love of the characters, the love of the relationships, is as strong as I’ve ever done.”

Irish actor Cillian Murphy, who has appeared in other Nolan films like Batman Begins, Inception, and Dunkirk, stars as Oppenheimer.

The cast also includes Florence Pugh, Robert Downey Jr., Matt Damon, Emily Blunt, Rami Malek, Josh Peck, Casey Affleck, Dane DeHaan, Benny Safdie, Jason Clark, Kenneth Branagh, Matthew Modine, and Jack Quaid.

Also Read: Cillian Murphy on the ‘[Expletive] Huge’ Responsibility of Playing Oppenheimer

Nolan says the mind-boggling quality of Oppenheimer is entirely on purpose.

“Oppenheimer’s story is all impossible questions. Impossible ethical dilemmas, paradox. There are no easy answers in his story. There are just difficult questions, and that’s what makes the story so compelling,” he says. “I think we were able to find a lot of things to be optimistic about in the film, genuinely, but there’s this sort of overriding bigger question that hangs over it. It felt essential that there be questions at the end that you leave rattling in people’s brains, and prompting discussion.”

Christopher Nolan Says Oppenheimer Could Potentially Be Considered a Horror Movie

Nolan calls the real-life moment when Oppenheimer pressed a button that had a small chance of destroying the entire world “the most dramatic moment in history.” The director also acknowledges that the film can be seen, in a way, as a horror movie.

“It is an intense experience, because it’s an intense story. I showed it to a filmmaker recently who said it’s kind of a horror movie. I don’t disagree… as I started to finish the film, I started to feel this color that’s not in my other films, just darkness. It’s there. The film fights against that,” he says.

“I was relieved to be finished with it, actually. But I enjoy watching the film tremendously. I think you’ll understand when you see the film. It’s a complicated set of feelings to be entertained by awful things, you know? Which is where the horror dimension comes in.”

So, if you plan to see Oppenheimer, be prepared to see something horrifying, and maybe even to be rendered at a loss for words. But don’t feel the need to do too much research about the story beforehand, Nolan says.

“My feeling on Oppenheimer was, a lot of people know the name, and they know he was involved with the atomic bomb, and they know that something else happened that was complicated in his relationship to US history. But not more specific than that. Frankly, for me, that’s the ideal audience member for my film,” he says. “The people who know nothing are going to get the wildest ride. Because it’s a wild story.”

Oppenheimer arrives in theaters in the U.S. on July 21.

Main Image: Cillian Murphy as J. Robert Oppenheimer in Oppenheimer. Photo Credit: Universal Pictures.