Recs.
Updated
A sci-fi colony sim driven by an intelligent AI storyteller. Inspired by Dwarf Fortress and Firefly. Generates stories by simulating psychology, ecology, gunplay, melee combat, climate, biomes, diplomacy, interpersonal relationships, art, medicine, trade, and more.
SpecsUpdate
Pros
Pro Unique gameplay, endless replayability
RimWorld is procedurally generated, and can create very interesting stories. There is a huge diversity of events and things to do in this game, from romance and affairs to natural events and mechanoid raids. There's always a reason to start a new game, even after horrific failure, and no two runs will EVER be the same. Watch the trailer to get a little taste of the gameplay - it's slightly outdated but carries the point across.
Cons
Con Can be overwhelming to those new to the genre
Anyone who knows Dwarf Fortress and the incredible micromanagement skills it takes can relate to RimWorld. There's a lot to learn, and while you can easily tone down the difficulty and make things nice and slow, if you've never played simulation games this can knock the wind out of you.