Fans of Squid Game will instantly recognize the scene. Along one wall, three sets of doors swing open, and 456 track-suited competitors slowly make their way inside, awed by the spectacle before them. The room is painted with fields of wheatgrass and bright blue skies, evoking a sense of calm and serenity that’s only disrupted when they see what’s standing directly opposite them: a 14-foot doll whose Exorcist-reminiscent head swivels will determine all of their fates.
That’s right: It’s time to play Red Light, Green Light, and in the reality competition series Squid Game: The Challenge, both the doll and the stakes feel as colossal as they are in the original show. Unlike creator Hwang Dong-hyuk’s Squid Game, where there’s nearly a full episode of exposition before the games begin, the unscripted adaptation jumps right in, and Red Light, Green Light is an ambitious first act.
In order to create a safe environment for 456 players to play the classic childhood game, the set had to be huge. So huge, in fact, that they had to use one of the largest indoor spaces in Europe, Cardington Studios, located in Bedford, UK. Used in the ’20s and ’30s as an airship hanger for building zeppelins, Cardington is over 100,000 square feet of indoor space, making each hangar roughly the size of four traditional soundstages.
Safety consultant Livia Pinto tells Tudum that the sheer size of the space, combined with the fact that so many people had to play at the same time, meant that safety was of chief concern. There were external factors at play: Temperatures in the UK during filming were very cold, so making sure players were warm enough throughout the day was important. Pinto says that hand warmers were distributed to players, and tented areas were outfitted with heaters for breaks between filming. There were also medics standing by at all times, ready to run through the crowd at a moment’s notice if someone in the sea of green raised their hand and called for them. And then, of course, there was the game itself. The process went through many rounds of testing with the production team and external testers standing in — but nothing could prepare them for what the day of filming Red Light, Green Light would actually look like.
“It was going to be different with the real players,” Pinto explains. “They’re going to run, potentially push people. Our main concern was making sure the [safety] briefing covered everything.” Pinto says that players were strictly warned not to push, shove, or otherwise risk the safety of their fellow players. If they did, they ran the risk of elimination.
The actual area where Red Light, Green Light was played has some impressive dimensions as well: The length of the room from starting line to finish line is 328 feet, and players could spread out across the width of the room, which is roughly 131 feet. In other words, the 456 competitors were stopping and going at short intervals across a space roughly the size of a football field — and had to do so in under five minutes and only when the massive mechanical girl in pigtails had her head turned.
Replicated exactly from the original show via 3D printer, the doll was one of the biggest technical challenges in the show.
“The head had [to be] fast enough to be fair,” executive producer John Hay explains. “If the head turned too slowly, people on one side of the field would get longer [to run] than people on this side of the field. If it turned too fast, it just flew off.”
In addition to being outfitted with mechanics that allowed her head to turn during the game, the doll served as the giant, menacing centerpiece for a state-of-the-art motion tracking system — even though she wasn’t doing any of the actual tracking herself.
“The doll is there to tell them when to stop moving,” executive producer Toni Ireland tells Tudum. “The cameras are behind the doll, watching everyone. If the doll was tracking people with a head turning, she was never going to catch [everything].”
The team perfected the tracking system via thorough testing ahead of filming. The space was outfitted with 16 cameras to detect any hint of motion from the players, each of whom wore a tracking device under their clothing.
“The motion tracking system used for Red Light, Green Light really started when we built a simulator — a bit of software that could simulate 456 people playing the game,” technical consultant Bryn Williams explains to Netflix. “We used that to develop a system that could track the players.”
The cameras and motion sensors reported various kinds of motion as well, including illegal yards (like someone moving forward after the doll’s song ended), foot stabilization, and even tiny bits of “dithering” motion, like a player rocking back and forth. Each movement was recorded and sent to a team of adjudicators whose primary task was to rigorously assess and sign off on every elimination, ensuring fairness.
Squid Game: The Challenge players implemented a variety of strategies to stay still throughout the game, including hands in pockets, crawling, and even crouching into a full-blown squat. However, those who couldn’t deceive the motion tracking system’s hawkish lenses met an eerily similar fate (only visually, of course) to the characters in the original show. In addition to the trackers worn in their jackets, players were also outfitted with a wearable squib, or ink pack. The squibs were built into customized vests tailored to each player’s body — when a player was eliminated, a small air canister in the vest triggered the ink to shoot up a nozzle and explode through their white tee shirt. The effect is impactful — and dramatic enough to ensure that no player was left questioning whether or not their game was over.
And there was certainly no shortage of eliminations. The object of Red Light, Green Light (both in the original show and the reality competition) was to exit players in large numbers before they headed to the dorm. It worked: At the end of Red Light, Green Light, the game went from 456 players to 197, adding a whopping $2.59 million to the piggy bank. If that wasn’t enough, you also got a taste of who this frantic horde of identically dressed competitors actually were.
“We’ve always wondered how we’re going to get a story out of this show, and Red Light, Green Light proved that we had an amazing story straight away,” executive producer Stephen Yemoh says. “We had two players who were mother and son, and the son crossed the finish line before his mother, and we had this amazing moment where he’s watching to see if his mother was going to make it across the line. It went down to the very last seconds… everyone was transfixed.”
Watch Squid Game: The Challenge on Netflix now.
