Speedrunning as a videogame phenomenon is not something we talk about often in strategy games, although, by design, grand strategy games do lend themselves to the craft. We've previously reported on one fan's speedrun in Crusader Kings III, and now a new one has cropped up in Hearts of Iron IV.
User CrossMountain has posted a run on the HOI4 subreddit in which they managed to re-form the Roman Empire by October 20, 1936, which is just shy of ten months after the game starts. In this timeframe they fight two wars, and take over enough of Europe to be able to trigger the event that lets you bring back the Imperium Romanum.
Like most Paradox Development Studios titles, Hearts of Iron IV provides goals in the guise of formable nations. Some are authentic or at least historically plausible, but others are just for fun. The Roman Empire formable nation is a bit of a meme at this point, as it gets put into nearly every PDS game regardless of whether it'd make sense or not (like during WWII).
RELATED LINKS:
Hearts of Iron 4 cheats - a guide to the best console commands
Looks like Paradox grand strategy games are collectively more popular than Civilization and Total War
Hearts of Iron IV devs are going to shake up the strategy game's stale meta