There aren’t many saloons where you can get into a decent pistol duel nowadays. But at the Mariposa in Sweetwater, you can walk in, order a shot of bourbon, and straight-up Aaron Burr a robot—all to the strains of Radiohead and Nine Inch Nails, courtesy of a player piano that happens to be ever so slightly out of tune. “That’s the twist,” says Ramin Djawadi, the composer for HBO’s Westworld. “In the show, everything is so real, until you look closely. The music is a subtle layer of that."

Djawadi is no stranger to scoring an epic HBO drama; he also composes for Game of Thrones. But *Westworld, *which wraps up its first season on Sunday night, depends on a tension that's rooted in reality rather than Westerosi legend. To heighten the contrast between the dusty prairie town of Sweetwater and the sterile, glass-walled control center, Djawadi chose entirely different instruments: acoustic guitars and harmonicas for the saloons and plains of the park, synthesizers for the futuristic laboratories.

At times, Djawadi further amplified the disconnect by using the same songs in both worlds, just using different instrumentation. “We wanted the control room to still feel Western, to be gritty and tough, like in the park,” Djawadi says. “But visually, they’re very different, and you can support the separation between the two worlds sonically.” The same piece of music feels entirely different when played by acoustic guitar and fiddle (Teddy riding the train into town), or by synthesizers (lab techs evaluating hosts' gun-slinging abilities).

88 Keys to Teasing Out Subtext

Maeve (Thandie Newton) and Dolores (Evan Rachel Wood) weren’t the first robots to blur the boundaries between hosts' programmed constraints and guests' autonomy: A more primitive technological creation did so from the opening scenes. The player piano in the corner of the Mariposa Saloon provides accompaniment to repetitive days in Sweetwater. Each morning, the characters unwittingly play out a Wild West-themed Groundhog Day, with the piano-only version of the show's theme song acting as the same weather report. “It’s been an amazing tool to seamlessly blend the background score into source music, as a subtle way of reminding the audience that everything in there is programmed,” Djawadi says. “Everything is on a time loop.”

As Maeve slowly uncovers the truth of her false world among the unsuspecting guests, she does it to tunes that many viewers—and, presumably, visitors to the park—-already associate with angst and melancholy. But these aren't dirges from the 1800s. Djawadi and Westworld creators Jonathan Nolan and Lisa Joy gave the piano decidedly modern tastes: The Cure; Soundgarden; Radiohead. (Lots of Radiohead.) So Maeve's journey happens against the anachronistic backdrop of “Black Hole Sun” and “Fake Plastic Trees”; by the time the piano plays an arrangement of Amy Winehouse’s “Back to Black,” Maeve controls her world entirely. “She’s making an active decision of breaking this time loop, and we actively picked a different song,” says Djawadi. “It shows she’s heading away from the repetition.”

Nolan’s deep love of Radiohead aside, the old-fashioned technology serves as the perfect foil for a show about futuristic robots living in a nostalgic recreation of the past. “The player piano was, and shout-out to Kurt Vonnegut for the idea, sort of the first, primordial version of our hosts: A Rube Goldberg machine that is created to evoke human emotion,” Nolan said at New York Comic Con earlier this year. Djawadi had never used a player piano before—he had to outsource the construction of the paper roll to Gnaw-Vol-ty Rolls, one of the few companies that still creates material for the instrument—but his creation provides fittingly anachronistic audio to Westworld. At least, until the player piano becomes sentient and starts wielding a knife.