Inspiration for one of the summer’s hottest games came from the simplest of places: The playground.

While spending time with his children in parks and playgrounds, Rob Jackson, the lead artist on Fall Guys: Ultimate Knockout imagined the silly chaos of hordes of kids bouncing off slides and through monkey bars.

The thought helped him craft the game’s colorful levels and its unathletic but try-hard bean characters, a term the game’s creators did not coin but acknowledge. The model is simple but gripping. The player controls the “bean,” which is designed to look like sweets, through a vivid obstacle course, trying to make it through to the next round. The last bean standing wins.

“The character is specifically designed to be the least appropriate to be participating in the game he’s in,” Jackson told Digital Trends. “They have maximum motivation but minimum physical capabilities, but they never give up. They always keep going.”

There are other inspirational touchstones as well. Ice cream, candy, stickers, vinyl characters, and even course-driven game shows like and all played a part in forming the game’s aesthetic.

There wasn’t an aha moment at developer Mediatonic’s headquarters when pitching the game, but the team did have a sense of what they wanted to create, Jackson says.

They wanted it to feel bright and colorful, safe and silly, but also chaotic and loose. They wanted the contrast of a game where a player needed to have some skill but also knew that at any moment something could go wrong.

To meet the game’s deadline, there were crunch issues, the developers said, complicated by quarantines. Launch day was especially chaotic. Too many people wanted to play, and the servers couldn’t keep up. The team of 48 scrambled. The game’s official Twitter account pleaded for patience, and unruly gamers took to Steam to review-bomb the game. Other gamers positive-bombed it back.

“Everyone watched the numbers with stunned amazement,” Jackson says.

A week after its launch, it sold 2 million copies on Steam and accrued 23 million hours watched on Twitch, according to numbers provided by Mediatonic. For the week of August 17, was the No. 1 overall game throughout Twitch and YouTube, beating goliaths like , and .

The game was featured as a free game for PS Plus members, and although Mediatonic won’t discuss sales on that platform, all signs point to a successful launch there as well.

Piers Harding-Rolls, a gaming analyst at Ampere Analysis, says it’s the way the game expertly joins chaos and color. The team at Mediatonic took the playground and candy inspiration and gave players of all age a real change behind the fun visuals.

“It combines many elements of the most popular games that are available today in a unique package. It is both familiar, drawing on other types of entertainment, for example, [It’s] social, easy to play, and competitive,” Harding-Rolls says.

A big part of the appeal is character customization. Players can change outfits, patterns, colors, and gestures. Options include versions of popular video game characters like Gordon from or seemingly random costumes like a pineapple. Gamers use in-game currency, Kudos and Crowns, to purchase these aesthetics. Therein lies another draw. Kudos is awarded after each playthrough, or show, based on how well you competed. Crowns, however, are only given to winners with a few thrown in as leveling-up rewards. This also keeps the player coming back for more rounds.

“The gameplay has some depth and strategy to it, so longer-term players will continue to find it engaging,” Harding-Rolls says.

Even the signature bean characters are loaded with unnoticed detail. Getting the physics right took time. Take it too much in one direction and you have the feather-lite movement control of a too loose and it moves like a bad mobile game, jerky and hard to control.It was important that it felt fun. It was important that a player would root for them.

“We wanted them to struggle,” Nicolas Pessina, Associate Lead Artist on the game, said. “We wanted the characters to look like a running joke.”

There were technical issues to consider as well. Because there are up to 60 players on screen at once, the design had to be simple. Though, it wasn’t always that way. At one point, the characters had knees and a neck.

Despite the chaos of launch day, the game’s popularity doesn’t seem to be waning anytime soon. Mediatonic recently announced it is going to release a mobile version in China. There’s no official word about a Switch or Xbox version, but that doesn’t seem out of the realm of possibility.

Jackson and Pessina said the hard work was worth it when they were able to see the audience’s reaction to the game. For Pessina, the success sank in when he saw one of his favorite streamers, Chance “Sodapoppin” Morris, playing the beta.

“To see him play the game, I was like, ‘what!’” Pessina said.

Jackson’s surreal moment was in the same place that inspired the game in the first place: The playground. There, Jackson heard children talking about the game, having no idea they were so close to someone who helped create it.

“I’m super grateful for all the love,” Jackson said. “We have a great community. Oh, and go yellow team. Yellow team is the best.”