"What else are we going to do, another f***ing platformer?": Mewgenics took 15 years to dominate Steam, but its secret sauce was cooked up in just 2 weeks

Some of what makes the success of Mewgenics – a game that blew through its creators' expectations and became the biggest roguelike in Steam history – so gratifying is the feel-good nature of its story. It's the result of two long-time collaborators reuniting on an idea lost and rediscovered over the course of 15 years, eventually releasing to rapturous critical and commercial success. But, set back by cancellation and copyright complexities, the road to its release has not always been smooth – not least because its creators didn't know what to do with it once they got it back.

"When we got the rights back from Team Meat, we knew we wanted to start over from scratch," Mewgenics's Edmund McMillen tells me. When we speak, McMillen and his co-creator Tyler Glaiel have just discovered that the years they put into this extremely long-awaited project appear to have paid off, its critical success making Mewgenics the best-reviewed game of the year so far. That success, however, was the product of more than a little uncertainty about what form the game would even take.

"There wasn't a tonne of the original prototype," McMillen explains. The idea of breeding cats remained from the earliest iterations of Mewgenics, but little else survived a process that had seen the project consigned to the litter box and only renewed once McMillen regained the rights to the game in 2018, several years after leaving original developer Team Meat. But while Mewgenics' core concept was still intact, an important question remained: Once you had the cats, "'what are you using them for?'"

Cat-stle Crasher

McMillen and Glaiel experimented with a few different concepts. A prototype in the style of co-op hit Castle Crashers was abandoned because it would have required multiplayer in order to have the squad of cats the pair wanted. After that came a real-time strategy game in the style of Warcraft 3, with a control scheme styled after Diablo. A few other ideas were floated, but it wasn't until the beginning of 2020 that the pair landed on the grid-based format that Mewgenics would eventually become.

"It was immediately obvious that that was the way to go," McMillen says. Almost a decade after its original inception, Mewgenics was finally "up and running basically in two weeks." Unfortunately, both McMillen and Glaiel knew from personal, painful experience that the road ahead of them would be hard. This kind of grid-based strategy is "very difficult to get right," Glaiel explains, "because you can't rely on reflexes to balance fights." In a real-time experience, a fight that's 2% too hard can be slowed down by 2% to give players a better chance. In turn-based strategy, "the actions are very careful, the systems need to be solid." McMillen had tried and failed to make games like this twice before, and Glaiel's development archives are home to four "unfinished RPGs." This time, however, something was different.

"At the time we started working on this, it did feel like we had made a lot of games," Glaiel says. "We learned a lot from all the other games we had made, individually and together." The pair told themselves they could try again, in spite of the "monumental" appearance of the task in front of them. "'Why shouldn't we be able to? What else are we going to do? Another fucking platformer?'"

Cat-tention to detail

Whether it was their development skills honed over the years, or the desire – if not need – to do something new that drove them, it seems that Mewgenics fell relatively easily, if slowly, into place. Asked how the pair handled the game's enormous list of skills alongside the genre's complexity, McMillen explains the pair "haven't iterated" much on the original ideas. Over the eight years since reacquiring the rights, McMillen sat down with Glaiel to rebalance Mewgenics' 1200+ abilities "just a handful of times," often driven more by their own increased understanding of the game than actual development roadblocks.

That confidence was driven by the pair's fondness for Magic: The Gathering, and specifically the random, synergy-seeking chaos of its notoriously complex Powered Cube mode. A twist on the on-the-fly deckbuilding of Draft modes in which anything goes and any card, no matter how overpowered, could appear in your hand, it's an obvious influence on Mewgenics, which might throw any combination of enemies, arenas, and abilities on any given run. With each new balance pass, McMillen and Glaiel would survey their diverse group of testers to seek out any real outliers, but bringing hundreds of different skills in line proved surprisingly straightforward.

That headache-free process, however, was not always mirrored by the player experience. Like The Binding of Isaac and Super Meat Boy, Mewgenics is not afraid to be challenging. Some time before launch, Glaiel shared stats that showed that after testers had invested 5-10 hours, they would likely go on to play for several times longer than that - but getting over that initial hump could prove too attritional for many. For McMillen, that enduring design philosophy is a case of wanting "to treat others the way I want to be treated, and I want to be treated like a person who has a brain." Glaiel recounted multiple stories of early players complaining they'd just barely scraped through a punishing boss fight – a marker he described as "the bullseye of difficulty" the pair are aiming for. "What are you challenging yourself for?" McMillen asks. "I know that's very common in video games, that people will just hand it to you, but I don't think we feel the same."

Clearly, that approach has paid off. Mewgenics' early critical acclaim was matched by financial success within hours of launch. But the 15-year mythology of the project meant doubts persisted until long after McMillen had regained the rights to Mewgenics. "Halfway through making this game," Glaiel explains, "I feel like we realized that it wasn't just a good game, that we were making something actually special."

That realization - that Mewgenics had the potential to become an all-timer - helped lift some of the weight of expectations from the pair's shoulders. But it also meant that Mewgenics had to meet that potential, to actually release as a game worthy of its predecessors, and of the 15 years it had spent in the public eye, even if the actual development window was less than half that long. For McMillen, whose greatest concern during development was that he'd roped his long-term creative partner into a project that might remain unfinishable, seeing that payoff was surreal: "The crazy thing is to read reviews that say 15 years was worth it. They assume that we've been working on this thing forever, and they think it meets the expectations of a game that people have been waiting for for 15 years. That's crazy."

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