LOS ANGELES – In adapting the popular Fallout video games for television, writer-producer Jonathan Nolan had a lot of creative freedom.

This is because of the open-ended nature of the gaming franchise, which has players exploring a post-apocalyptic nuclear wasteland full of mutants, monsters and rival factions.

Nolan, who is British American, co-created the series with his Taiwanese-American wife Lisa Joy, with whom he also wrote the Emmy-winning science-fiction drama Westworld (2016 to 2022).

But unlike Westworld, which was based on a 1973 science-fiction western film about a theme park populated by androids, the Fallout games are open-ended.

And this presented both an opportunity and a challenge, Nolan says at a virtual press event for the series, which debuts on Prime Video on April 11. It stars Ella Purnell as a member of a community that has lived in underground vaults since the nuclear blast, and Aaron Moten as an ambitious soldier.

These characters’ journeys capture the essence of the game, says Nolan.

“One of the reasons I love these games is they’re open-world role-playing games. You get to decide where you want to steer the story,” the 47-year-old tells reporters.

“Which means a rigorous adaptation is sort of impossible. If you play the game, you might play it as a good guy who joins this faction; I might play it as a bad guy who joins a different faction.

“There is no one version of any of these games – and there are seven games,” says Nolan. He, with his brother Christopher Nolan, the Oscar-winning director of war drama Oppenheimer (2023), co-wrote the science-fiction movie Interstellar (2014) and superhero film The Dark Knight (2008).

But all the games share a distinctive tone, which  Jonathan Nolan and Joy tried to replicate in the series.

“You have these beautiful worlds that are the common character in all the games, but the tone is also so unique and so odd. It’s dark, violent, political, satirical, funny and goofy,” he says.

He recalls playing the games for the first time in the late 2000s.  “I’d never experienced anything quite like this cocktail of all of my favourite things.”

Whether this mash-up works as well on TV as it does in gaming remains to be seen.

“Bringing these things together is either going to be a disaster or, hopefully, it gives you the same feeling I got playing those games for the first time,” says Nolan, who has a son and a daughter with Joy, 46.

And while they had plenty of leeway with the storytelling, the couple tried to capture the aesthetic of the games as best they could.

“In most places, because the story and characters are original, we wanted to have a high level of fidelity to the games in the costumes and the props,” Nolan says.

For inspiration, the creators looked to all seven Fallout games, which were released from 1997 to 2018.

“But we looked at (2015’s) Fallout 4 more, and (2018’s) Fallout 76 a little bit, for the specific design elements,” says Nolan, who also directed the first three episodes.

There is, however, one innovation he is rather proud of.

“We stuck human fingers in the mouth of the Gulper,” he says, referring to a terrifying salamander-like creature that has mutated from the radioactive fallout.

“It’s one of those things you sometimes pitch as a director, and everyone just goes, ‘Okay, that’s gross, let’s not do that.’

“But as we got deeper into it, they went, ‘What about that weird finger idea you had?’”

Nolan reflects on the path he has taken since he first broke into Hollywood with Memento (2000), the neo-noir thriller based on a short story he wrote. He and his brother shared a Best Original Screenplay Oscar nomination for it.

“I’ve been blessed in my career to be able to work on things I’m passionate about,” he says. “And I was passionate about these games.”

• Fallout debuts on Prime Video on April 11.