The Castle Doctrine is described as 'The Castle Doctrine is a massively-multiplayer game of burglary and home defense. It's 1991, and things are bad. You're a guy with a house and family. Other players are coming to take what's yours. Build security to stop them' and is an app. There are five alternatives to The Castle Doctrine for Windows, Linux, Flathub, Steam and Flatpak. The best The Castle Doctrine alternative is OpenDungeons, which is both free and Open Source. Other great apps like The Castle Doctrine are Evil Genius, Dungeon Keeper 2, OpenDungeonsPlus and The Mighty Quest for Epic Loot.