‘Netflix had shown us their interactive capabilities, which were relatively rudimentary at the time. They’d done this thing called Puss in Book, and they showed us Buddy Thunderstruck and Stretch Armstrong, which were also kids’ animations and fairly linear. It was mainly “which of these two scenes do you want to watch?” and then you go back to the main branch, and there were slight pauses. And we were like, “that’s very interesting, thanks.” And went out of the room and said, “No way we’re going to do anything to do with that, it looks gimmicky.”’

It’s not surprising that a seasoned gamer would reject what essentially looked like a reinvention of 1990s full-motion video FMV games, which Brooker tells me he remembers as ‘rubbish’. But then, during a meeting about story ideas for Black Mirror, everything clicked.

‘I’d wanted to do another episode that was set in the past, and for ages I’d wanted to do something about old games. I had a vague idea about something buried within the code of an old game that surfaces years later. Then we had this other idea kicking around for ages, a sort of comedy Terminator. A future civilisation that sends a tiny earpiece back in time to change the future. Stopping Hitler’s grandparents meeting, something like that.

'But the joke was that it goes to the wrong person. They’re in the past, they have to take instructions from somebody in the future. As often happens, all these ideas sort of came together, and we realised we could use Netflix’s interactive storytelling tech.’

BRITISH GAMING NOSTALGIA

Bandersnatch wasn’t a comedy Terminator or a ghost-in-the-code story. Instead, Brooker wrote about possibly the most niche and least international culture in tech history, the 1980s British bedroom coder. Nostalgia is big business, and games are having a retro moment, but Brooker thinks some portrayals of gaming history are a bit revisionist. ‘I don’t remember playing Super Mario Brothers on the Nintendo Entertainment System,’ he says.

‘I know the Nintendo was a thing in the UK, but it wasn’t the biggest thing. For me, early consoles were things like the Atari, and that was something posh people had. For me, the Sinclair ZX Spectrum was the people’s computer, a very British computer. There was a strange cottage industry around it of idiosyncratic programmers, often on their own, creating these very weird little things. A lot of them went a bit mad, got burn-out or were terribly exploited.

‘But some of them have gone on to become behemoths in the game industry, and you can still see the DNA of that time in games such as Grand Theft Auto. It feels to me that it’s the part of the same lineage. So, I thought, that’s an era and a place in time and history that I haven’t seen dramatised very often.

‘There was a BBC Four thing called Micro Men, which was about Sir Clive Sinclair, but it wasn’t about games. I think they mentioned Elite or something like that, but I hadn’t seen anything about people trying to write games on the Spectrum and that whole world, which to me was such a massive part of my early teenage years. That was why we went for that setting.’

In Bandersnatch, 19-year-old amateur coder Stefan Butler (Fionn Whitehead), is adapting an interactive fiction novel (also called Bandersnatch) by Jerome F. Davies, a fictional author played by games legend Jeff Minter. In the original script, Stefan explicitly describes the book as a branching narrative novel written in the 1960s that was ‘way ahead of its time’.

Brooker explains, ‘The idea was there was this author who was a sort of Tolkien, Philip K Dick type, this groundbreaking guy who had invented the format. That was the backdrop, and there was crossover between fantasy fiction, dungeons and dragons and video games at that time generally.’

Those references didn’t make it to the final version, but they’re obviously in the DNA of the episode to those of us who remember the time. One reference that did make the cut is The Hobbit game, which Brooker admits he never completed as a kid. ‘Mohan Thakur (Asim Chaudry), the founder of video game company Tuckersoft says, “There’s no ‘get lamp’ or whatever”, because we thought we’ll make it so the game he’s developing is a bit like what we’re doing on the Netflix platform. So, he says, “Oh, it’s an adventure game, but you don’t have to type anything in, you just make choices. You’ve got ten seconds.” He literally tells you how the Bandersnatch episode works.’

Brooker seems delighted at having brought these rather obscure references to a major international television show. ‘Something that does always amuse me is the thought that Bandersnatch has gone up on Netflix, people all over the world have seen it, and it became a talking point on social media, and what they’re watching is someone in 1984 in Britain typing away on a rubber keyboard, complaining about the sprites flickering and talking about The Hobbit game,’ he says.

SINCLAIR’S LEGACY

The rubber keys, of course, refer to the ZX Spectrum that Bandersnatch on which character Stefan Butler codes. Brooker says it’s the machine he most associates with teenagers of that era. He was a ZX owner himself from the age of ten, when he found a ZX80, which he describes as ‘like a white ZX81 but with an even crapper keyboard’ in a jumble sale at a village fete.

‘It must have been about 1981. I remember it was £5 in the jumble sale, so I begged my Dad for an advance on my pocket money. I was incredibly excited to have a computer in my house. For me the goal was to get Pac-Man at home. Then I realised quite quickly that the ZX80 was dogshit, it couldn’t do anything, but it had a manual and there were some really simple things you could type in. There was a game called Cheese Nibbler. It would draw a grey block on the screen comprised of other blocks, and every time you pressed the key, one of the blocks disappeared. Then at the end it would tell you how long it took you to press to make them disappear. That was the game. Cheese Nibbler.’

He later begged for the classic ZX Spectrum as a joint birthday and Christmas present. ‘I had a 16KB Spectrum to start with, and there was a decent version of Space Invaders on there. That was really exciting. I would get Computer and Video Games and magazines like that, which had programs written in the back that you could copy.

‘I remember having a speech synthesis pack for it, but you couldn’t plug the joystick and speech thing in at the same time. I suppose that was what I liked about the Spectrum, it was very homebrew. It felt to me like the computer that Doctor Who would have had. It was cheap and cheerful, and a bit crappy, but you would sort of hit it and it would work.

‘What was most fascinating to me was the notion that you could control something on the television. I’d always been obsessed with television, and now suddenly you could alter what was happening on it yourself with your hands, which was basically amazing.’

INTERACTIVE TELLY

Ten-year-old Charlie Brooker probably wouldn’t have predicted he’d go on to make a major mainstream interactive television episode, but it seems a neat progression of his early TV and games obsession. Some Bandersnatch viewers, however, have expressed frustration. One of the scenes features a TV games reviewer giving a star rating to Stefan Butler’s game.

In order to achieve the five-star review, the viewer has to take the most difficult and Stefan-torturing path. Some viewers disliked this compromise. There’s even a fan edit on YouTube, which shows Stefan completing his game, getting a five-star review, and living happily and healthily ever after.

‘This is the closest we get to supernatural in the Black Mirror universe,’ says Brooker. ‘The original idea was there’s some old evil that Jerome F. Davis stumbled across, this terrible knowledge about multiple realities. It was meant to be a bit sort of Quatermass, a bit Nigel Kneale. That’s why if you get the Pearl Ritman (Laura Evelyn) ending, it flashes forward to the present day.

Pearl is then seen working on an adaptation of Bandersnatch for Netflix and she starts to be influenced like Jerome F. Davis was. The idea was that the game is sort of evil, forcing itself into existence and making Stefan do bad things. It’s a tricky one, because I’m in two minds as to whether we should have included an ending where it’s possible to make everything great.’

Some of the criticism also focused on whether Bandersnatch is enough of a game, with some viewers complaining that the in-episode choices are too limited. Brooker is aware of this limitation, but explains that the episode went through rigorous testing to ensure it made sense to the average Netflix viewer who might not be a gamer.

‘If you’re trying to tell one story, choices have to be limited unless everything is going to be unsatisfactory. Originally, every time you failed, it would take you back to the start, and people got confused and frustrated, so we came up with a split screen. One screen gives you the option to go back and undo what you just did; on the other screen there will be, contextually, something you haven’t done yet. If you have done things we think are important, it will just show static.

‘Some people said, “Well this isn’t interactive because I just threw tea over the computer and it just made me undo it.” But no one complains when Mario falls to his death then comes back. No one goes “well Nintendo isn’t really giving me much freedom of choice here!” We have to limit it somewhere.’

I suggest that wanting to get a five-star review and also make Stefan happy is a gamer mentality, going for what seems like full completion. Brooker agrees. ‘That’s the thing, and it frustrated some people who came at it with that sensibility, which I can understand. I want 100 per cent. I want to get the gold medals. I’ve completed the mission, but I only got bronze. Weirdly, though, we never thought people would try to finish it.’

GAME OR FILM?

Whether it’s a game or a film is a subject of debate, even within the Bandersnatch production team. Brooker’s attempts to make it more of a game caused some internal friction, but ultimately the broader Netflix audience needed to be considered. ‘We rarely disagree, usually we’re all in unison, but philosophically, there was disagreement over how gamey this could get, and what constitutes an ending. I wanted to introduce Achievements, even if it was just a little badge – “you found the messy tea drinker achievement”. They all had a funny little name and icon.’

‘I thought that was an easy thing for people to compare, but in the end it was left out. There was another fundamental difference in opinion over how much people would re-engage with it once they hit an ending. I knew that people on Reddit would rinse the whole thing within ten minutes (although they still worked out the ZX Spectrum Easter egg quicker than we anticipated), but that’s not most people. That was one of the reasons why we simplified things as we went along, to facilitate casual viewing.

‘One criticism that’s slightly frustrated me is that some games people have said, “Well this is nothing revolutionary.” Which is true, and much more sophisticated games are available, but ultimately, what’s different is that it isn’t on a gaming platform. It’s on Netflix and we have to be very mindful of somebody who has never encountered this, and would actively not be interested if they thought it was a game. We had people like that who work on the production who were like, “I don’t want to think of this as a game. I’m only interested in films.”’

While Brooker was pushing Bandersnatch in the direction of being a game, he acknowledges that he wasn’t aware of the size of the jump for viewers who had never played a game. ‘I think there was a general view that we needed to do a bit more hand-holding,’ he says, ‘which I do think was right, but I found frustrating. I would often push it as a game. Originally, there was a central puzzle that only made sense once you’d died several times. That was also the reason why we encourage you to fail early on, because we figured most people would accept the job at Tuckersoft, although not as many people as you’d think.

‘It’s all about presenting the best possible version of your story, and you’re presented with several versions as soon as you get into the game space. Some of them are going to be better than others, and It goes against every fibre of your being to make it so that people could miss something. I kept saying, “It doesn’t matter, it’s fine because people will go on the Internet and they’ll see that there was another thing and they’ll go back.”’

PLANNING THE THREADS

Writing a Netflix film that’s also a game, or a game that’s also a film, was uncharted territory for the Black Mirror team. Brooker thought he could just plan the episode as a flow chart on a whiteboard, but when Netflix said it could make the episode ‘remember’ choices, such as whether the viewer had a key in their pocket, he turned to Twine, an open-source tool for creating interactive stories.

‘Every time I looked at Twine, it looked baffling, but it reminded me of planning a script. You’d write bits on index cards and stick them on a wall, it was very similar to that. But I think script writing is a form of coding anyway; you’re writing a set of instructions in a really formal language and you can literally get mistakes in it.’

Brooker shows me the script and code in Twine on his laptop, which is tracking whether character Colin Ritman (Will Poulter) is alive or dead. He tells me about an earlier version, a much more game-like puzzle that would certainly have baffled the average Netflix viewer.

‘It annoys me that we couldn’t quite make it work but a remnant of it is left. There’s a branch where Stefan’s got a phone and can’t remember the number. We show you the number in a flashback. Originally, that was a central puzzle. The idea was that you couldn’t complete it on your first go. Every time after Stefan had killed his dad, he’d go to the phone, try to ring Dr Haynes (Alice Lowe) and he couldn’t remember the number.

The viewer wouldn’t know what the hell is going on. You’d be going “what’s the number? I don’t know what the number is!”, and then every time you failed, you’d be given a recap of what you’d done so far, and it would get a bit shorter each time until you get the number after several playthroughs.

‘There’s literally dialogue like “get a pen. If you listen carefully, you can hear the numbers. Five,” and the idea was that the edit would get more and more compressed, but it didn’t work. The first problem was translation into other languages. Problem number two was that test viewers didn’t understand it, even when the characters were literally saying “here’s the number”. People couldn’t remember the number for more than 30 seconds, and they were confused and frustrated. So, on my part, with great reluctance, that chunk came out and we re-edited some stuff.

‘But we kept a remnant of it, because the idea was always that you’d get to a point where suddenly you get the numbers zero to nine and you wouldn’t know what to do. A lot of the work I did was working out that stuff. Having to know where you were, how many times you’d seen it. It’s got quite a sophisticated system of showing you edited versions of what you’ve already seen, which I think people don’t quite pick up.’

INTRODUCING BRANCH MANAGER

Eventually, keeping track of all the branches and the script proved to be too big a job for Brooker’s existing software. As it became more apparent that he needed custom software, Netflix started developing Branch Manager, a program that’s actually seen on-screen in the episode during the ‘Pearl Ritman’ ending. It was a huge relief to Brooker.

‘I can now import stuff straight from Final Draft into Branch Manager. But beforehand, those tools didn’t exist. I thought I’d just have to use Twine to write the outline, then use it for the script, and give it to the actors on an iPad or something so they could literally click on it. I was digging around online trying to find a plug-in that lets you just paste in your TV script, and there isn’t one.

‘I ended up using Scrivener, Final Draft, Twine and something else, and it was just this weird round-the-houses way of cobbling the whole thing together. That was a real pain. If there was any change, I would have to go back to the start of the chain.’

Bandersnatch, which Brooker describes as ‘deliberately experimental’, also served as a way for Netflix to give Branch Manager, which will be used for other interactive shows, a thorough workout. As Branch Manager was developed alongside the episode production, decisions that didn’t work in earlier versions of Bandersnatch and were removed would, Brooker says with some frustration, ultimately have worked by the time they got to the end of the production.

‘Originally, there were loads more choices at the start of the episode, and it’s a bit annoying we cut them out because they’d improved the system by the time we got to the end. For example, when Stefan goes to Tuckersoft, that’s where you were previously able to tell him to bite his nails or pull his earlobe. Later, he mentions it to the psychiatrist and that would have been a more powerful moment if you’d been getting him to do those things earlier.’

The cereal choice at the beginning only trivially affects later footage, with an advert for your chosen cereal appearing on videotape, but it was almost a much more important decision. ‘In Earthworm Jim, you can launch a cow at the start of the game,’ says Brooker. Then, when you get to the end, if you launched the cow it falls down and squashes someone. I think it squashes the final boss if you’ve done it at the very start. At one point I wanted to do a cow launch moment with the cereal.’

Choices in Bandersnatch are presented via on-screen text. Black ‘letterbox’ bars appear at the top and bottom of the screen to visually prompt the viewer. It’s a direct nod from Brooker to gamers, who are used to the screen changing when the player has control. ‘It just felt like a subliminal small thing we can do. There is a joke in it, when his Dad lifts up the two boxes of cereal – in my head, that’s what all FMV games were like in the 1990s, where the world would stop while you chose. There was a lot of pushing from my side about making it more gamey.’

TECHNICAL CHALLENGES

The end result is near seamless, nothing like the slow-loading FMV games of the 1990s. ‘Originally we were working within strict technical parameters,’ says Brooker, ‘and we knew we had to have a certain amount of footage playing before we could present you with a choice, and that choice had to last a certain amount of time.

‘We thought there would be a small gap as it pulled in the next clip, affecting the sound mix. It wasn’t seamless, even when we were playing directly off our hard drive. There was a little pause and I was resigned to that. I kept saying, “What would be a dream if it just kept going,” and Netflix said, “We think we might be able to, on very high-end devices, get it almost visually seamless, but there will still be audio dropout,” which obviously affected the mix. But now if you listen to the 5.1 version, it’s literally seamless audibly, as well as visually. That staggered me.’

It turns out that, like most video games, there are also bugs in Bandersnatch. ‘Right up until the end, we still found some bugs. There’s a bit that it’s impossible to access, which is annoying because it’s a nice little scene at the start when Stefan meets Colin Ritman. There’s a third version of that scene where Colin knows everything, but you can’t get to it.’

It’s understandable that Netflix had to compromise when presenting a brand-new concept to its audience, but it’s also clear that Brooker’s original vision for Bandersnatch was more of a game. In an early meeting, he suggested a VR version and even an app on which the viewer could make choices, as Netflix can track numbers. It could introduce random elements, such as a dice roll, a la Fighting Fantasy books, and also open up storytelling options.

‘When originally had the phone number puzzle, I realised that people would immediately find out what the number was and put it online,’ he says, ‘so the game was going to know if it was your first time round. If you put the right phone number in straightaway, Colin Ritman would answer and tells you to stop being a cheat. I then I wanted to change the phone number to a random one, so it was different every time. That was possible in principle, but those sorts of things are for probably version three of this sort of thing. For version two, I would love it if they wheeled out the unlockable achievements.’