Cataclysm: Dark Days Ahead. It’s a free, classic-style roguelike that has a massive amount of options. The game takes place in the near-future following an apocalyptic event that has turned most people into zombies. There’s also Lovecraftian horrors, Fallout-esque military installations guarded by robots, the ability to be a furry (like, with a full costume. Or you can get mutagens and transform yourself into an animal hybrid.), vehicle and structure building, and you can even milk cows. It’s updated daily if you want to play the latest test builds, or you can stay with the latest stable build. There are various overhaul mods and loads of single-feature mods. It’s one of my all-time favorite games, and I tend to go back to it every few months.