It’s Dwarf Fortress — with a less-awful UI, no Z-levels, and reworked skills.
For the uninitiated, this is a genre where you build a little base for a bunch of near-suicidal dudes and try to keep them alive. The gameplay driver is the kind of storytelling that happens when one of the dudes in your fort of drunkards wants nothing more than to run outside to retrieve some burning clothing during a siege. Losing is !!fun!!.
If you’re new to the genre, you’ll probably find the UI here annoying. The UI in this game is an improvement over DF, but it’s still opaque, with layers of build commands. There’s plenty of room for further accessibility improvement.
This game is pretty fun, and there’s some extra subgame here with making caravans and entering other areas from the world map. It’s definitely worth playing, if any of this sounds interesting to you.
My experience with Rimworld today: While most of my dudes were 3 days away trying to rescue a prisoner, a local group of slavers attacked. As our walls burned (and the pacifists cowered in the jail cell), I sent a tamed alpaca to the megaspider cave as bait. The slavers had numbers, and shotguns. The megaspiders had a ravenous hunger for manflesh.
Now we have to deal with the cold snap that killed off the crops, and repair the charred walls. Our chef’s a cannibal so ‘finding food’ might not be a problem, but, y’know, the bodies are over in the cave. Tonight we starve, and hope the spiders are satisfied.
@ DF vets: As above there are no z-levels here, and also no shenanigans like quantum stockpiles or infinite power. (As far as I can tell at 55 hours in, anyway, although I’ve barely scratched the surface. I might be wrong!) You won’t be doing megaprojects here, this is just (improved) early-version DF, with random events and world map excursions to shake things up. Your forts will be wide and flat, but the game will throw interesting things at you. Definitely worth checking out if you’re tired of building megabeast-guarded forts underneath the HFS.