Ultima Ratio Regum [official site] is like the world generation side of Dwarf Fortress, except zoomed in a little and with more attention paid to the specifics of cultures rather than the verging-on-cosmic legendary events of the past. It's a game that procedurally generates civilisations, faces, cities, religions, clothes and symbols. Perhaps it's wrong to describe it as a game at present, actually, as the April 2016 release of version 0.8 will be the first "gameplay release". At the moment, it's a tool (or series of tools) that create worlds and the people who inhabit those worlds.
The latest work involves procedural castles and they look amazing.
First, let's be clear on one point, Ultima Ratio Regum is not fucking around. These procedural castles aren't simply made up of blocks randomly dropped into place to make something that's a bit castley. The specifics of each castle are drawn from the culture that built that castle. That's how URR works, you see - there's an implied history in all things so a procedurally generated castle shouldn't seem like a structure that appeared one day, it should fit into its surroundings., as if it grew from them.
"What goes into a castle? Castles are located in cities and take up a full district in that city. As I've talked about before, policies/ideologies have been completely reworked to provide physical and structural changes to each nation, rather than more abstract things. Therefore, the 'Zealotry' ideology has religious buildings spawn in all city districts; the 'Conscription' ideology places a barracks in every town; the 'Isolationist' ideology creates city walls; 'Theocracy' always ensures a crypt beneath a cathedral; and so on. I've now extended this system to castles, meaning that the rooms you find inside each castle (aside from the standard halls, guard quarters, etc) are entirely dependent on the ideologies of that nation, and forms a kind of microcosm which reflects the city around it (and all the people in that nation, and its towns and settlements, and its citizens, and so forth)."
That means an Imperialist nation's castles will have trophies adorning their walls, celebrating conquests and the glory of the Empire. Those who believe in penitentiary justice will have dungeons in their castles and those who support the monastic lifestyle will have cloistered areas for their monks.
"This therefore means that each castle can have a range of special rooms, from the smallest possible number of two (I think!) for a nation where almost none of its polices necessitate special rooms, to a grand total of sixteen rooms for a nation which happens to have chosen ideologies which necessitate something special (and everything in-between). As ever I wanted castles to reflect the aesthetic/geometric preferences of each nation (square, octagon, circle, diamond, cross) and also, of course, to actually look like a castle on the outside with walls, moats, and so forth. This leaves us with a 'two part' castle system – generating the outside of the castle which is the 'district' of the city, so to speak, and then generating the inside of the castle."
You can read more about the castles in the latest dev update.
The next stage, to prepare URR for that initial gameplay release, involves a lot of work on "human scale" pathfinding and scheduling. All of this is genuinely more exciting than bombastic trailers.
You can download Ultima Ratio Regum's latest release (April 2015) right now. The current build is intended for use on Windows but there are instructions for Linux and Mac play.