We go behind the scenes of Sony’s PlayStation 4 adventure game.

“Games, as opposed to any other medium, are much stronger if you get it right.”

It’s now less than a month until the launch of Until Dawn, the PlayStation 4-exclusive horror title from developer Supermassive Games, and creative director Will Byles is equal parts energetic and nervous. It isn’t just the normal anxiety of a developer about to release a game years in the making – though that’s there as well, of course. But for Byles this emotion seems multiplied into a strangely respectable uncertainty about his own game, a project that’s trying something new, something he believes in even as he’s unsure how the industry at large will react. "I’m not saying we have got it right," Byles clarifies, giving away his nervousness once more. "But if you get it right with storytelling, there’s a ridiculously strong precedent in games. Everything you do is first-person – I mean, not first-person camera, but it’s first-person in the sense that you have agency." Until Dawn has received a lot of comparisons to titles like Heavy Rain or Telltale’s The Walking Dead. That is to say, it’s a narrative-focused experience, a game that’s more about playing through a story and making certain choices than any traditional mechanics. But even more so than those examples, agency seems to be the key word for Supermassive Games.

Choose your own adventure The source of agency in Until Dawn is a system that Supermassive Games called "the Butterfly Effect." This is a reference to a theory coined by meteorologist Edward Lorenz stating that a small change at one point in time can lead to massive changes later on. The classic example that the theory draws its name from: A butterfly flaps its wings on one side of the world; some indeterminate amount of time later, a hurricane forms on the opposite side of the world. The butterfly may not be precisely responsible for the hurricane, but the ripples of its flapping wings added to the forces that led to the hurricane. For Until Dawn, these heady ideas are meant to come together in one important truth: Every tiny choice you make throughout the game will come together to form the story that is told and your eventual outcome. The most obvious example, and the one Until Dawn has built most of its press on, is how every character in the game can live or die depending on your choices. The story follows a traditional horror movie structure, with a group of eight friends heading out to a cabin in the middle of nowhere for a getaway. When your game ends, you may have defied the odds of the slasher genre and kept all eight of these friends alive. Or, if you chose poorly, every one of them could be dead, even the obvious "survivor" trope main character. But, if Byles is to be believed, character deaths are really only the most shocking and obvious part of the Butterfly Effect system. Dozens, if not hundreds, of tiny choices are made throughout the game, and they can impact everything from the relationship between two friends to how much of the overall mystery you actually end up uncovering. "There’s no empirical answer really to how many decisions you make throughout the game," Byles says. "There are thousands, literally thousands of endings. In fact, I think it’s millions. But that’s not because there are millions of different endings. It’s just that the mathematical permutations of eight people, all of whom can live or all of whom can die in any order in any number of ways. It just gives that many permutations. And that’s just on endings." Byles says he "can almost guarantee that there will be no two people on the planet who will take the same path through the game." There are events in the story that will happen no matter what through the course of a playthrough, but he also mentions "a huge amount of content" a player will never see if they only play the game once. The hardest challenge Supermassive faced was keeping all these threads straight for themselves. Before even starting work on Until Dawn’s script, the developer created custom software that could map out every choice in the game. Byles describes the software as a series of linked "nodes," each one branching out until it hits another choice that branches out and so on. "All of those are networked together," he says. "We can basically run the system through and see what works without necessarily having to play the game." At their smallest level, these nodes break down into branches off of each conversation in the game. Every time two characters talk, the player can choose a response for whichever character they’re controlling at the time. Each response splits off and can move the conversation down a whole new path. And subsequently, those responses can affect the characters’ relationships with each other or how they grow as the game progresses. "There’s one character who starts off the game a bit of a prat," Byles says. "By the end of the game, he can end up as a real douchebag, or he can end up as a complete hero. His character arc changes throughout the story based on your choices." If you’re playing as the jock boyfriend Mike, as an example, and choose not to stick up for your girlfriend Jess, she’s going to start liking you a lot less. This could affect the overall fate of these two characters in the end, but more notably it will change how she responds to you, what direction your conversations go in and how individual scenes play out. In an early preview build Polygon received last month, we were able to play through the first several hours of Until Dawn, including a bunch of scenes as Mike and Jess. We played Mike as the faithful, protective boyfriend, improving our relationship with Jess at every opportunity. Before the preview build’s climactic scene, Jess and Mike retire to a cabin for some alone time. Because we got their relationship to the highest level possible at that point, Jess did a playful striptease and undressed all the way down to her underwear. What initially comes off as cliché slasher genre cheesecake is actually an example of Until Dawn’s complex relationship system at work. Jess can be either incredibly warm or very cold to Mike depending on how your relationship has evolved in the preceding hours. "It’s quite hard to do that," Byles laughs, when we tell him that Jess stripped to her underwear in our playthrough. "That’s based on how much of a jerk you are on the way up. There’s a whole bunch of times you can be a complete jerk, a whole bunch of stuff you can get wrong, and then she’s going to be fully clothed in that scene." With hundreds of tiny choices impacting hundreds of tiny changes throughout the game, Supermassive Games has had to do an incredible balancing act during development. Byles admits that the whole structure of Until Dawn is "a house of cards." He explains how every time the team had a change they wanted to implement to the story, they had to look at how it would affect other events. Inevitably, the ramifications were enormous and "we’d have to set entire days aside to look through the knock-ons of what we were doing."

The sound of terror Supermassive didn’t just have to invent a new way of organizing narrative for Until Dawn. The developer also had to search for new ways to piece together music. To accomplish this, Supermassive Games senior sound designer Barney Pratt turned to an industry veteran: Jason Graves. Graves has been a composer for dozens of games, but he got his start in the horror genre with EA’s Dead Space series. Back when he was pulled on to that project, Graves helped create a new method of implementing music with a game. "We kind of established a precedent for how we used layers of music to help scare players," Graves says. "The game engine would determine how the layers were getting turned up and down and what was getting triggered. You’d get a mix of sounds the whole time. There was stuff constantly moving behind the scenes. That worked really well from the first Dead Space through all the other titles I’ve worked on." That is, Graves explains, up to Until Dawn. Because of the ambitious Butterfly Effect system, Graves had to throw out his traditional method of allowing the game engine to tweak music on the fly. "Any one scene could play out so many different ways," he says. "You couldn’t really sit there like you could in a corridor shooter, where you’re walking down a hallway three or four minutes, and it’s very on-rails. For that, you can use one piece of music that’s very long, but it’s looping and everything’s fading in and out. That doesn’t work in Until Dawn." To further explain why this traditional system wouldn’t fit Until Dawn, Graves provides an example: Say there’s a point in the game where the character is running from a killer. You have a choice to hide under a bed or to run down the hall. One choice calls for tension as you wait to see if the killer finds you; the other requires the adrenaline of dashing past your potential death. "There’s really no way to use the same piece of music for both," he says. Before becoming a respected game composer, Graves got his start working on film scores in the mid-'90s. In the end, he turned to this experience to find a solution that would work for Until Dawn. "You have to score every one of these scenes like a film," Graves says, recalling the moment he came to this revelation. "You need to have it scored to picture. The point of Until Dawn is to have really unique gameplay, really unique outcomes. You need to have really unique music for each situation as an extension of that." As they worked out this method, Graves and Pratt spent "the equivalent to days of time" in discussions before any music was even recorded. Then Graves led three orchestra recording sessions over the course of a year. This was three years ago. That’s how far in advance Supermassive Games needed the music to be able to tie it to every single scene individually. The recording sessions themselves were unique as well. Graves says the orchestra put together around 30 minutes of themes for the characters of Until Dawn. These pieces were what he calls "actual music that had melody and chord progressions." But the vast majority of the sessions were devoted to recording smaller pieces of atmospheric audio, bits that could be layered on top of each other to create a mood during any given scene. Graves calls these shorter, more flexible recordings "puzzle pieces." "We probably did eight to 10 hours worth of puzzle pieces," he says. "But all of those were then reassembled and stacked and shuffled and everything else to match up and underscore the gameplay." When creating these creepy tidbits, Graves says he often fell back on standbys such as 30-second violin loops. The scariest instrument, he says, is "whatever instrument someone can listen to and not recognize. "You hear this sound, and you can’t picture what it is. Your brain can’t relax. Even if you don’t realize it, it’s trying to figure out what it is. Let’s say it’s strings doing freaky little footstep sounds. Your brain starts thinking, ‘Is that rats? Is it mice?’ Whatever little insects or rodents might disturb you personally. Everyone interprets it a different way. It’s not anything specific; it’s general and unkown. And the unknown is really scary."