It took Twitch viewers four hours to figure out the puzzles in Porsche’s latest ad, an interactive playthrough where viewers controlled the IRL actions of two drivers in order to reveal the team’s newest electric car, the Porsche 99X. As Twitch’s Adam Harris told Digiday, the Choose Your Own Adventure-style game was aimed squarely at a younger audience of 18- to 34-year-olds who weren’t already targeted by traditional TV and radio advertising. The ad was a collaboration between Twitch’s internal brand studio and Porsche. The old-school carmaker approached Twitch about six months ago with an idea: it was joining Formula E, the electric racing league, for the first time, and it wanted help reaching the young people who might be interested.

“They sent us a challenge,” Harris, Twitch’s director of custom solutions in Europe, says when I reach him by phone. “They said if we were going to reveal the Formula E car for them, how would we do it?”

The answer, naturally, was a game — but not just any game. “We wanted to do something completely unique with it, which was actually make a real-life video game,” says Harris. The team drew from well-loved espionage games: Harris name-checked Hitman, Metal Gear Solid, and Resident Evil when talking about the project’s inspirations. Porsche provided a facility in Stuttgart, Germany, and Twitch turned the drivers into protagonists for the audiences to play. “We were able to construct a narrative,” says Harris, “which was the Porsche drivers had to solve a host of game-related puzzles to break into the facility to then reveal or unlock (in gamer speak, as we refer to it) the Formula E car.”

The game itself was pretty straightforward: players solved those puzzles and snuck the drivers past “guards,” moving the drivers around through that Stuttgart facility as though life itself were a Choose Your Own Adventure game. That meant collectively voting for preset options in the stream’s chat. (At one point, the stream told a driver to hide from a guard using a cardboard box.)

To Digiday, Harris likened the ad to Netflix’s experiment with interactivity: Black Mirror: Bandersnatch, which let viewers navigate a maze of choices to guide a young programmer to his fate. But on its face, Porsche’s branded game seems more like Twitch Plays Pokémon, which was a fan-coded experience that let viewers play their way through games in the Pokémon series by voting on which buttons they should press.

It was the second-biggest stream on Twitch during the hours it was live

It’s not hard to think of what this means for Twitch: the kind of experience Porsche put together is, to put it mildly, premium. It costs a lot to run an ad like this. (As Digiday reports, it could cost anywhere between $2 and $20 per 1,000 views, which, in the world of internet advertising, adds up to a big chunk of change.) And while the experience was a little buggy, it was a success: the experiment averaged around 28,000 viewers while it was live on Porsche’s channel, and Harris says there were “almost a million” people playing across those four hours. It was also the second-biggest stream on Twitch during the hours it was live.

That means we’ll probably see more of these kinds of advertising events from Twitch. Harris says conversations with Porsche about doing more work have been ongoing. “We’d love to love to do more with Porsche, and we’ve started to speak about that because it’s been a huge success for both parties,” he says, although it wouldn’t say whether there were more IRL games in the works.

It’s likely that we’ll see more brands partnering with Twitch for similar experiences. As Harris says: “If you pitch it in the right way and you come up with the correct kind of concept and narrative that has the community pulling together, they really engage and embrace this kind of content.” Organic engagement, remember, is the most valuable kind of all.