RimWorld is a colony sim, but that undersells it. It is really a story generator, with an AI storyteller sitting behind the scenes deciding when to throw a heatwave, a raid or a wandering stranger at your little band of survivors stranded on the rim of the galaxy.
The magic is in the disasters. A perfectly organised colony falls apart in the most memorable ways: a beloved colonist goes berserk, a solar flare knocks out the freezers, and suddenly you are narrating an epic in your head about the survivors who held the line. Every save becomes its own saga.
Hours vanish here, and I regret none of them.