Hearts of Iron IV

Hearts of Iron IV is a grand strategy wargame from Paradox Development Studio (published by Paradox Interactive) in which you take command of any nation in World War II. You refight the war at the head of a state of the era: building an industrial powerhouse, forging diplomatic alliances and waging war on ideological opponents.

It is more than a historical simulation: almost every decision opens alternative paths, from small ones such as where to strike to crack Fortress Europe open, to large ones such as whether to re-establish democracies or long-forgotten monarchies. You design division templates almost down to the rivets, research new means of production and destruction, give factories their instructions and pursue political goals. There is also multiplayer, and the Steam Workshop adds mods.

According to HowLongToBeat, a “story” run takes about 52 hours and a full one more than a thousand (about 1,158), though the sample is small. A month certainly won’t be enough for a full run, but it is plenty for one or two campaigns. There is single-player against the AI, which needs no connection, and multiplayer over the internet.