So if you’ve played Rimworld it’ll feel familiar. Much more complex but part of that complexity is because you can traverse the Z axis, and make multi-level fortresses. I don’t think Tarn has ever recoded to allow multi thread processing, so everything runs on a single CPU core (my info may be out of date). If that’s still the case, then the end of every fortress (that doesn’t succumb to a mood spiral or a were-beast or an elf invasion or the circus or forgetting to pack an anvil or vampires or a cavern collapse) is fps death. Usually from cats. But remember, losing is fun!