This was a great system to sink my teeth into -- you did a lot with the space you had, and I feel like this is a complete system that could even support a small campaign. Pretty impressive for 1(-ish) page!
Favourite details: I really like that the PCs aren't central to actually solving the city's predicament. There's something to be said for games about heroes, but it's great to see a game about people just trying to keep things afloat. The setting is also great... kind of reminds me of an even more post-apocalyptic Blades in the Dark. I like that the Talents are suggestions, not set; I like that there's a mechanical reason to lean into personality flaws. It comes together really nicely.
Would be nice to have: If there's one thing I'm left wanting, it's protagonists that have a little of the same weird and wild vibe of the setting! There's mad kings, reality fog, rat forces, and a city on the edge of nothing... but the PCs could be in more or less any fantasy realm. Which, like, totally works, don't get me wrong. But I wouldn't mind at all seeing some example prompts of weird supplies, or Callings, or Traits.
Anyway. Not at all surprising this is really well-written, given your equally strong work on HOBS -- but props where they're due, this is neat. Thank you for sharing.