It's a strategy game set in the Second World War. You can play as pretty much any nation in the world. There is a mod that adds anarchism,liberterian socialism and other ideologies into the game.
Steam- https://store.steampowered.com/app/394360/Hearts_of_Iron_IV/ Windows, Mac and Linux
or torrents https://scenegames.goodolddownloads.com/game/hearts-of-iron-iv (Windows only)