South Park has offended just about everyone in its 20 years on air. The animated comedy’s equal-opportunities approach to controversy means no target is off limits in its sharp satire.

But sitting with the show’s creators, Matt Stone and Trey Parker, at South Park Studios in Los Angeles, the pair say they haven’t pushed any issue too far… yet. “We’re about to,” promises Stone. “At the end of October people are going to tell us to leave. We’re ready.”

That’s when the duo will unleash new video game South Park: The Fractured But Whole (“It was going to be The Butthole of Time, but they said we can’t say butthole,” Parker reveals), taking aim at targets high and low — from institutionalised racism and paedophile priests, to Hollywood’s superhero deluge.

“Our ethos has always been: if it’s funny it’s funny. Everyone can be made fun of, and everything should be made fun of if you do it in the right way,” says Parker.

Each wall of the office shows their success in that mission — two decades of South Park memorabilia, the marionettes from 2004 film Team America: World Police, and posters for the phenomenally successful stage musical The Book of Mormon.

Every episode of the TV show is scripted, recorded and animated just days before broadcast to stay as topical as possible. It’s an approach that’s difficult to translate into a game developed over a number of years.

“It’s totally different, and we’re not totally great at it,” Parker jokes. “Our game was hard to make because we didn’t want it to be, ‘here’s a funny cut-scene and now here’s a dry puzzle’. The puzzles need to be funny, and the funny stuff needs to have gameplay. They have to be interwoven and talk to each other.”

The writers frequently re-wrote during the game’s development to update the gags — and claim that some are oddly more topical now than when they were written. “It’ll be funny when people get to it, we’ve just been living with it for two years,” says Parker.

'I didn't recover from Donald Trump's election night for a month' Trey Parker

The Fractured But Whole gets even closer to the look of the series than 2014 game South Park: The Stick of Truth, which launched to acclaim from critics and fans of the show. This time the character models and animation techniques of the series have made their way into the game engine, and the sword-and-sorcery fantasy theme has been swapped for a superhero showdown.

“Farts are your power, time farts,” Parker confirms. “We were committed to the farts and the butt thing.”

South Park’s new season has now begun with episodes skewering the white nationalist tiki torch march, Columbus Day and Amazon Alexa. There’s less of a focus on Donald Trump, whose election campaign dominated the last season. Stone and Parker were taken by surprise when Trump won the election, and had to rewrite an episode at the 11th hour. Even they struggled to see a funny side.

“It was a shocker,” Stone says, recalling that night. “The entire last season was about that, so we’re a little burned out on it. We don’t have a joke to make.”

Parker adds that the election took him a whole month to recover from. “We were up forever getting the episode under control. We got something that was OK, but you could tell what we’d done to fix it.”

Before Trump, Stone and Parker satirised the Bush administration and al Qaeda in Team America, and while Stone says they’re “yearning to do something” in film again soon, it won’t be an Islamic State update on the puppet comedy.

“It’s all the same s***,” he says. “It’s like, ‘Ooh, are you going to do something on North Korea?’ We did.”

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Their biggest export of recent years remains The Book of Mormon — still one of the West End’s most in-demand shows (“It was a f***ing good idea,” Stone says). Initially beginning life as a music project, the show almost became a film before arriving on stage. “We’re both most proud of the second act,” says Parker. “Both as a fan and a critic of musicals, second acts usually fall apart.”

Stone agrees. “You’re that far into it and it keeps unfolding. I love in a musical where you’re like, ‘Woah, we’re over here now?’ The songs wrote the musical, and that’s what makes it good. It wasn’t like, ‘Let’s do a show and then stop for a song, and then more show, and stop for a song’.”

As any Book of Mormon audience member will attest, the move from post-watershed TV comedy to all-singing Broadway show didn’t force Stone and Parker to lose their edge. “By the time we get to them singing ‘F*** you, God’, we’re doing the most insanely irreverent s*** but we’ve earned it. We didn’t just start there, we got there by building plot,” Parker smiles. “But we sprinkle shavings of gratuitous on top.”

Follow Ben Travis on Twitter: @BenSTravis

South Park: The Fractured But Whole arrives on PS4, Xbox One and PC on October 17