This piece was commissioned by and written for Pitchfork.

You shouldn’t expect the new space-exploration video game No Man’s Sky to have anything in common with Guitar Hero or Rock Band. One glance at screenshots show a compulsory video game gun in the lower right corner, a spaceship zooming around, or a wanderer gathering minerals. But what those screenshots don’t demonstrate is how No Man’s Sky is, unexpectedly, the latest entry into the canon of games that integrate and let you play with music in new ways.

This is hardly the single boldest claim the game can make. Any sedate description of No Man’s Sky is shrouded in hyperbole: It uses algorithms to generate 18 quintillion planets with their own distinct atmospheres for players to explore simultaneously. Its 20-person team was profiled in The Atlantic and in two separate New Yorker stories, and it’s perhaps the first “small” game to get a late-night guest spot when Stephen Colbert’s “Late Show” broadcast an 8-minute demo last October.

On top of all that, the game’s soundtrack doubles as the new album from electronic post-rockers 65daysofstatic. Sort of. Music for an Infinite Universe isn’t the game’s score in any conventional sense. Although the Sheffield, UK band is returning with more thrashing guitars, buzzing drones, anthemic drums, and noodling soundscapes, what’s different on this album, their seventh, is all of its instrumental tracks and textures were dismantled and chopped up by Hello Games. Then, both the band and Hello Games composed and recorded supplemental elements for a living, breathing, and adapting video game score. Their collaborations are about the least complicated aspect of the game: Hello Games’ managing director Sean Murray reportedly emailed 65daysofstatic, his favorite band, screenshots in 2013 asking if they could their song “Debutante” to score the game’s debut trailer. From there, conversations persisted on how they could work together more ambitiously than using pre-existing material.

From the moment you decide to hop in your ship to the moment you decide you’d rather duck into a cave than scour the surface of whatever planet you’re on, how you play moment to moment dictates how and what the game’s score performs. Although this isn’t the first time something like this has been done in video games (earlier instances include Monkey Island 2 in 1991, utilizing an interactive music engine that allowed different characters and locations to alter the arrangement of a piece you were already hearing), this is the best and most integrated attempt.

Every sonic element of the score is managed by Pulse, a generative music system audio director Paul Weir built for No Man’s Sky. Pulse monitors how you play through various lenses, called levels of interest. Since the game can’t read a player’s mind directly, the system was constructed around information it can reliably measure.

A screenshot of Pulse.

“We can’t tell what he or she is going to do on that planet,” says Harry Denholm, the game’s senior programmer. “But we can tell whether they’re going to a planet or they’re approaching a space station for the first time, or they are breaking atmosphere for the first time, or they’re about to engage with some pirates.”

And while No Man’s Sky is capable of serving up more traditional accompaniment for times when you are locked in battle, with menacing guitars and synchronized pounding drums and soaring bass, the twist here is what sounds like a fully composed piece of music from a 65daysofstatic song is actually being arranged on the fly based on what you’re doing. Admittedly, it’s an abstract feature designed to be seamless and difficult to intentionally parse. Don’t think of it as each move you make triggers an aural shift; it’s more about your general pattern of behavior being the muse for assembling deconstructed musical phrases from an already completed album. It’s just a coincidence that what you’re hearing sounds like familiar action-movie tension.

Furthermore, despite the game’s compulsory gun, No Man’s Sky is touted by Hello Games as more of a chill-out experience. Think of it as a sci-fi Second Life for loners. You can shoot up harmless creatures, what you’ll be hearing more often while exploring are throbbing drones, murmuring piano refrains, or scratchy soundscapes perforated by soothing syncopation. But if you choose to unholster and lay waste, you’ll be flecked by jangling and skittering guitars.

65days’ Paul Wolinski (no relation) says the experience of providing a finished album, and knowing that would be the beginning of another creative process has changed the way they’re going to approach writing songs as a band. “We’re over the idea that an album is supposed to be a definitive set of ideas.” This is not necessarily a revolutionary statement, as many musicians faced with recreating recorded material live might tell you. As CD Walkmans and random play begat streaming-service algorithms as new ways to be made aware of a band’s work, this is a new way to be familiar with a band in a way they didn’t intend: by your remixing it invisibly while playing a game.

Pulse’s job is to prevent you from growing accustomed to how and what the music will do.

“The player may not specifically notice,” says Denholm. “The change in music is happening as the whole tone and feel of the planet is also shifting around them. The sun sets, darkness falls, bioluminescence glows in the shadows — moving to a new soundscape is here to help emphasize and underline that the environment has changed.”

“You’re not aware of the changes, and sometimes it just kind of enters your consciousness,” says Weir. “It’s quite clever, that it’s playing a bit of music just as you’re doing a certain thing, but hopefully you never think it’s [a 1:1] relationship. It’s more ambiguous than that.”

Indeed, when asked how many ways the player influences the soundtrack, both Denholm and Weir admit they’ve lost track. And although Weir insists “there’s nothing technically impressive about Pulse,” it’s clear it was built and deployed with an impressive amount of patience. While play testing through the game, Hello Games would routinely keep watch for where to build in an additional level of interest with its own criteria the player’s actions would influence.

For example, Denholm says, an early “level of interest” they identified was flying towards a planet. In a case like that, “You’re in space and there might not be very much else happening, but the act of flying towards a planet is actually a big deal. You’re exploring your map to discover somewhere new. It should be a moment for the player.”

And since each moment is as idiosyncratic and unpredictable as the person playing the game, what you hear described in this article may or may not resemble what you wind up hearing when you play. To potentially tee up so many variables, Weir remembers all the testing Hello Games did while making the game and along the way identifying another opportunity for the soundtrack to pivot based on what you’re doing. In the above example of heading towards a planet, Weir called the band and asked for 30 arpeggios in every key: “You put an arpeggio in and suddenly you get a sense of tempo and it draws you in.”

But it was all a lot of trial and error. And although 65days knew the album would be woven into the game and had some conversations about it, neither half really knew how that would work, exactly.

“For a long time, all we had was an album from them without really understanding how it was going to be introduced into the game,” admits Weir.

Part of it was nailing how it would work conceptually, which Denholm compares to moving multiple microphones around many rooms each with their own orchestra pits. The other part of the work was meticulously figuring out which instruments of the orchestra — in this case, a combination of disparate 10-second stems and a pool of samples — sounded best together and letting Pulse start cherry picking.

“It’s just data on top of data,” says Denholm. “Like, having plenty of that variation and being able to elegantly move between them and vary them.”

Still, Weir says the advent of Pulse is not about having another bullet point on the back of game’s box to entice potential customers. It was instead about enabling a specific type of creativity. Denholm agrees, adding that he’s skeptical this would fit as naturally with another kind of game or even with another band: “I don’t know if this works in every musical style or if it would work in every game style. The sheer sandbox procedural nature of the game really lends itself to this kind of approach. All the other complexity, we’re trying to murder ourselves with.”

“We’re absolutely firm believers of nothing being more complex than it needs to be,” Weir says, sincerely.

There’s an easy irony here in contrasting that against there being 18 quintillion planets in No Man’s Sky, but the reality is regardless of how successful the game proves and whether it gets sequel after sequel, the game allows players to compose their own worlds as they explore them. It’s a potential stepping stone that lets this game being played with more exploration focused on the sound than the sights, and could also open up other possibilities for other games that have yet to be imagined.