If you've ever had a perfectly good Mewgenics run absolutely demolished by a miniboss pulling the worst possible spell at the worst possible moment, patch 1.0.20870 has some good news for you. Developers Edmund McMillen and Tyler Glaiel have been pushing fixes at a steady clip since launch, and this latest update is one of the more meaningful ones, targeting both a genuinely frustrating fight and a crash bug so specific it reads like a fever dream.
The Arthur Problem, Finally Addressed
If you know, you know. Arthur is a miniboss whose entire deal is the Metronome ability, which randomly pulls from a massive pool of spells. Most of the time that's fine, even fun. But the old version of that pool included some absolute nightmare scenarios.
The worst offenders: Split the Atom, which hits every single one of your cats for 50 instant damage, and We Are One, which soul-links everyone in the battle. That second one is particularly brutal because it makes killing Arthur nearly impossible without wiping your own team at the same time. Bad RNG with either of those could end a run on the spot, no counterplay, no warning.
The patch trims those catastrophic outliers from Arthur's Metronome pool. He's still unpredictable, still a genuine threat, but the floor on how badly a fight can go has been raised considerably. That's a smart fix. The chaos is part of what makes Mewgenics great, but there's a difference between exciting unpredictability and just getting blindsided by instant death.
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If Arthur was a fight you were actively avoiding on runs, it's worth giving him another shot now. The encounter is a lot more readable without those extreme spells in the mix.
The Patch Note That Will Live Forever
Here's the thing: most patch notes are dry. "Fixed collision on level 3." "Adjusted enemy spawn rates." Fine, useful, forgettable.
This one is not that.
Patch 1.0.20870 includes the following fix: "Fixed case where a non-binary cat with dwarfism would crash the game if playing in Brazilian Portuguese." That sentence contains more information per word than most entire changelogs.
According to Tyler Glaiel on X, the crash came down to how the game handles naming. Cats with dwarfism get the modifier 'Little' added to their name. In Portuguese, that word is gendered, so the game needs separate variants for male and female cats. Cats with the '?' gender had no variant assigned, the naming system hit an unresolvable state, and the game crashed. A very specific chain of conditions, all of which had to be true simultaneously, that only affected players running the Brazilian Portuguese localization.
The fact that this combination exists at all is a testament to just how many interlocking systems Mewgenics is juggling. The project has been in development for years, and the sheer density of traits, genetics, and language support clearly creates some extraordinary edge cases.
Self-Damage Abilities Now Actually Count as Self-Damage
A quieter but genuinely impactful fix: certain abilities that reduce your cat's HP, specifically Itch and Chonkwalk, were previously just deducting health without being recognized by the game as self-damage events. Now they are.
That distinction matters because several Fighter passives, including Dumb Muscle and Hulk Up, trigger specifically when a cat takes damage. Those synergies were effectively locked off from builds using those abilities. With the fix in place, a whole category of interactions opens back up, and players who enjoy building around self-damage mechanics have a lot more to work with.
The Steady Pace of Post-Launch Fixes
Beyond the headline changes, the rest of the patch is a long list of bug fixes that covers a wide range of issues players have been running into. Mewgenics launched with an enormous amount of content and overlapping systems, and McMillen and Glaiel have been visibly active in responding to what the community surfaces.
For a game this dense, that kind of attentive post-launch support matters. The Mewgenics news and media page has been keeping up with developments since launch, and with DLC already confirmed to be in the works, the foundation being built through these patches will matter for everything that comes after. If you've been holding off on jumping back in, this is a solid moment to return. Make sure to check out more:
