"This is incredibly rare": How Mouthwashing quietly became 2024's breakout horror hit

I first heard about Mouthwashing through a friend, who heard about it from Tumblr. This is quite bizarre if you know anything about Mouthwashing, a low poly, grimy horror game about the last days of the crew aboard a spaceship. It came out in September on PC, and like many indie gems, launched to some critical acclaim but didn't take off at first. But some time in October, word started to get around about this strange little game. On Tumblr, users had begun creating fanart and engaging in heated discussions about its characters, and who was ultimately responsible for the ship's demise. I then started noticing it getting picked up by streamers more, consistently showing up in my live recommendations on TikTok.

So one night, I decided to try it for myself. It only takes three hours to play, but by the end I felt like I had spent an eternity watching a small world crumble. The stories of these five people brought together by a space courier corporation called Pony Express and left to die is deeply depressing, and the claustrophobic mood of both the ship itself and their situation is palpable. Mouthwashing is bloody, tense, often disgusting, and tragic. I wanted to go lie down in a dark room and stare at the ceiling after finishing it. And I loved it.

Others loved it too, so much so that it's become a unique indie game success story. Despite it being a few months since launch, it's still going strong, gathering new players and selling more copies. It's also received nominations at The Indie Game Awards for Game of the Year and Best Narrative, and as game awards season continues, we can expect to see more love incoming. Basically, if you haven't heard about Mouthwashing before, you will very soon.

Who is responsible?

Mouthwashing initially appealed to many horror fans with its striking art style and pedigree. It was developed by Wrong Organ, creator of 2022's bizarre How Fish is Made, and published by Critical Reflex. The indie publisher doesn't strictly work on horror titles, but its focus on more abstract projects has resulted in some intriguing releases, such as 2024 viral hit Buckshot Roulette.

It launched on September 26, and according to SteamDB, it's accrued new concurrent players each month ever since – with October seeing a nearly 260% jump. Granted, this amounts to hundreds of players, which doesn't hold up against multiplayer games on Steam that can rake in millions of players over years, but for a single player title you can finish in an evening, the fact it's grown and sales have remained steady over the following months is rare.

Simon Carless, the founder of video game sales analysis firm GameDiscoverCo, says it's sold "at least 10-15x more lifetime copies on Steam compared to its first week sales numbers," which is largely unheard of for a short, lo-fi, narrative horror. A game like this would've maybe sold most of its copies in the first week, and dropped off into obscurity.

"This is incredibly rare compared to most games, which quickly decrease in sales over time," Carless says. "It looks like horror streamer enthusiasm in particular – and word of mouth – have really expanded its reach beyond normal."

These kinds of short, single player games can take off in ways more expensive projects might not. The threshold for success is obviously lower for a game that was cheaper to make, and not only was Mouthwashing made with a small team, it only took around 15 months to develop. Look at the Steam charts though, and you'll often see games the size of Mouthwashing sneak into the top. Some of 2024's most intriguing releases, like Balatro, 1000xResist, Indika, or Little Kitty Big City, are all getting critical and player recognition despite falling outside of what the big studios are publishing.

"Indies are able to take risks in ways that a lot of AAA games simply cannot anymore," says Johanna Kasurinen, Wrong Organ narrative designer and art lead. "That’s the blunt difference. Mouthwashing is a concept that would never have been picked up by most publishers or studios... Don’t get us wrong, we love AAA games as well. But there’s a large empty canyon between AAA and the indies that needs to be breached with small and medium scoped projects. Games that shine through their in-adherence to the norm moreso than their pedigree, graphical fidelity or conformity to cinema."

Horror game influencers can take credit for Mouthwashing's success as well. Its twisty, emotionally powerful experience makes it perfect for streaming to a wider audience. TwitchTracker says that viewers have watched nearly 176,000 hours of Mouthwashing on Twitch, and that's not considering the hours put in on YouTube and TikTok. Horror games are ripe for streaming, as many popular content creators can attest to, because there's a lot of potential for spontaneous, emotional moments that can go viral. It's also just entertaining to watch. Without going into spoiler territory, Mouthwashing has plenty of these, and only a couple of them are jumpscares.

"One way to determine if a title will resonate is to find something that will make you go, 'Woah holy shit!' and then try to assess whether this game caters to your very niche tastes or if others will have a similar reaction," said Rita Lebedeva, Critical Reflex founder, in an interview with Polygon.

It's done well even beyond the conventional means. Let's go back to Tumblr, where my journey started. It's a few months after release, and the top posts have tens of thousands of interactions. Searching for Mouthwashing on the site brings up countless pieces of fanart ranging from the thematically resonant to the distractingly adorable. It's been consistent too, and the developer has spotlighted many entries in its Steam Q&As. Even its eerie soundtrack has hit milestones, with 1 million people streaming it on Spotify as of November.

"That’s been one of the most surprising aspects of how this game has been received," adds Moore. "We were so hyped when we started receiving a few pieces of fan art and such but then all of a sudden there was so much that we couldn’t even keep track of it anymore. We appreciate anyone who is inspired enough by the game to create something, whether it be doodles or full blown animations or cosplay. It all truly means a lot to us."

Steering the ship

But what is it about Mouthwashing that has captured players? If fanart is any indication, it's partially thanks to the complexity of its characters. There are five crew members, and at first they all seem like your standard cookie-cutter shipmates: the nurse, the mechanic, the incompetent intern. Over the course of the game's runtime, you're steadily let into their lives, getting to know how they ended up on the spaceship Tulpar and why they all broke down over months stranded in space. Mouthwashing is a horror game, but it's also a tragic character study about how relationships are built and how they can transform into something bittersweet.

The imagery is also striking. The most iconic image is of Curly, the former ship captain who spends most of the game wrapped in crusty, uneven bandages staring at you with one bulging eye. It's a bleak reflection of a person in untold pain, and you'll get some great looks at him as you're forced to feed him medication or carry him across the ship. The situations he's put in while in that state are somehow worse (so much worse) than just watching him suffer on a bed, but only tangentially. Pony Express's mascot, a brown cartoon horse named Polle, would also fit right in with any number of mascot horror titles like Five Nights at Freddy's, with posters and statues littered across the ship smiling at the crew members with dead eyes.

However, there's an underlying cruelty to Mouthwashing that people seem to have latched onto. Tulpar is under contract with Pony Express, but its crew are laid off during their mission.

While there is a lot that leads to the Tulpar's downfall that you need to experience for yourself, the hammer of peak capitalism comes down hard on this ship. And when you exist under the umbrella of corporate rule for so long, what happens when the systems keeping you in place suddenly vanish? Will you continue to live by those rules? If so, will they morph you into something horrible? Who will suffer because of it? Can you be blamed for the actions imposed upon you by a system?

Mouthwashing is a painful, messy experience. It won't make you feel good either. Watching the events unfold leaves you feeling dirty or like you saw something you shouldn't have. But that depth, those surprises, and its very human story have appealed to many players. If its steady trend continues, you'll be hearing a lot more about it in 2025.

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