[This story contains mild spoilers for Netflix's Black Mirror: Bandersnatch.]

Black Mirror: Bandersnatch, Netflix's first interactive offering for adults, launched on Dec. 28 after a complicated two-year journey to bring it to the screen.

Black Mirror creator and writer Charlie Brooker told The Hollywood Reporter that making Bandersnatch was like making four episodes of the sci-fi anthology series at once and that, as a result, the forthcoming fifth season has been pushed back.

"We knew going into it that it would be difficult and challenging and more complicated than a normal film that we would do. Even then, we underestimated," Brooker elaborates to THR. "As the story expanded, I like to say that the story got longer and it got wider. So the whole thing started expanding a bit like an inflatable life raft in a small room."

The fifth season of Black Mirror, Netflix has confirmed, is set to release in 2019. Beyond that, no premiere date or episode count has been announced. Though the six-episode fourth season of the Emmy-winning series released Dec. 29 of 2017, Brooker and his partner, executive producer Annabel Jones, have not typically stuck to a yearly schedule. Miley Cyrus is the first actor to reveal her involvement in an upcoming episode, though neither Brooker or Jones would comment on the casting.

"Did you not get to that ending?" Jones cheekily replied to THR when asked about Cyrus, referring to the multiple endings of their choose-your-own-adventure-style movie. Bandersnatch is a stand-alone film and, while it might serve as a prequel to the entire series, it is indeed separate from season five. All of the episodes in the series are stand-alone stories, but they connect thanks to Easter eggs for discerning viewers, and Bandersnatch continued that trend.

Going into the project, Brooker assumed that, in terms of raw work, Bandersnatch would be like making two episodes of Black Mirror. It wasn't until the lead-up to launch that Brooker instead likened that number to four. "A lot of that is because literally the tools that we needed to create it didn’t exist at the start, so we were learning as we went," he says.

Indeed, Netflix worked with Brooker and Jones on a handful of new tech, including a Branch Manager tool that the streaming giant now plans to apply to all of its future interactive projects. But the interactive script program didn't arrive until months into Brooker's writing process. "There was quite a bit of trial and error of learning what would and wouldn’t work. Because you have to learn a whole new way of editing," he explains. "It’s not like editing a standard film where you can often rearrange scenes or cut things. In some respects you have more freedom because you have so many different stories that you can be telling. But then you are restricted in new ways. There’s a whole new language you have to learn and on top of that, you have to write and film so much more."

On top of that, Brooker and Jones have also been working on the episodes for season five. The idea for Bandersnatch, in fact, came out of a story-idea meeting for the new batch of episodes. "We knew going into it that this would impact our time, but it hasn’t stopped us from doing other films," Brooker says of working on other episodes simultaneously. "I think it’s fair to say that it took us more time and effort than we had initially anticipated."

The Black Mirror pair always likes to leave a sense of mystery surrounding the themes, genres and topics they will tackle in a new season, and the fifth cycle of their techno-paranoia series is no exception. One idea that Brooker did entertain was the possibility that Will Poulter's Bandersnatch character, Colin Ritman, could turn up in future stories. "Ostensibly, he could go on forever, because he’s both dead and not dead," Brooker suggested of the trans-dimensional character. "I like the idea that he could show up anywhere. I could see him popping up in 'San Junipero' or running around in 'White Bear.'"

Creating an impactful character like Colin Ritman is actually what turned out to be the most time-consuming feat of Bandersnatch. The biggest challenge for Jones was creating a cohesive world that had multiple endings that could all coexist for the protagonist (Fionn Whitehead), so viewers stayed emotionally engaged with his character, Stefan.

"Something like this is obviously a massive undertaking and bizarrely, the really time-consuming thing is holding onto that truthfulness," says Jones of creating a series of believable endings. "You could have created something like this where there were very dramatic and very big, disparate decisions for Stefan to make. But you might have ended up with a sprawling and incohesive story, which wouldn’t have been very satisfying. A lot of the craft comes from keeping the world as small as possible, but also keeping the world as emotionally impactful for Stefan as possible."

She continues, "There’s so much content and not reflected in the content is the craftsmanship, and what you have to take out to make the world exist — or feel as if it does exist in one cohesive world. So it did take an enormous amount of time and as a result, then season five sort of gets shifted back a little bit. But this is such a huge, interesting new opportunity for Netflix that we’re a part of. And there is so much fun to be had with it. That’s one thing that I hope people take away from it: I hope that you just enjoy the experience."