Dwarf Fortress - Dwarf Fortress is a single-player fantasy game with two modes: fortress and adventure.
Theme Hospital - Business simulation game created in 1997.
Domina - Domina is an Action, Strategy, Combat, and Single-player Simulation created and published by DolphinBarn.
RimWorld - RimWorld - A sci-fi colony sim driven by an intelligent AI storyteller.
DayZ - DayZ is an open world multiplayer survival game that tosses you in the midst of a zombie apocalypse.
RollerCoaster Tycoon Classic - Create and run amazing parks on your iPhone or Android.