Hands down one of the best games released out of Steam Early Access to date. If you took Prison Architect, a left kidney, the Sims, a few (seemingly rigged) dice and just about any post-apocalyptic drama show and threw them in a blender, this game is what you would be left with.

Not only does this game have tons of content and replay value but it also has a very lively modding community on the Steam Workshop should you ever get bored of carving people's lungs out (you won't).
Rimworld promises countless hours of ridiculous (mildly sadistic) fun.