I ran this as a duet for a friend and then we immediately swapped playbooks and went for another round. Fantastic game, really tense and fun. We both got spooked! Do give this a try, its really solid, thematic and takes about an hour to play (which is a great length).
And both games created very different stories! One was more about being stalked by something trying to rip off your flesh, the other was more liminal and psychological.
Ben nailed it already, so I'll just kind of post this as a longform agreement. We just defined the game as about cults (they're a core part of the campaign we're playing). I'm not sure how far I'd push my luck with trying to create different kinds of stuff, but if I ever needed to say, generate a host of new gangs for Blades in the Dark, or maybe immortal beings for a Lord of the Rings esc fantasy, etc etc, then I'd reach for this game again.
I'd also just play it as intended too, which I'm actually yet to do. It sits in a really nice place for prompting and easy creativity.
EDIT: In re-reading this, I've realised that I implied something without saying it. We had concrete truths as we'd been playing in the setting for a bit already. Magic exists. This is the normal technology level. Blah blah blah. Then everything above that layer is fair game as usual. We also all knew the intention of this exercise going in.
