RimWorld is one of the ‘original’ steam early access darlings, an excellent survival city builder game that drops you on the frontiers of known space and expects you to scrape a living surrounded by deadly mechs, weird aliens, and weirdos who most of the time want to kill you.
It’s a modern successor to something like Dwarf Fortress, an excellent management strategy game, and a wholly solo affair as far as the original design is concerned… but that’s not stopped people wanting to play RimWorld in multiplayer.