“Secret Hitler” sounds like boardgame you’d see in an episode of “Family Guy” or “South Park”, calculated to cause offense. It’s not unreasonable to suspect its creators, one of whom created the equally offensive (and entertaining) “Cards Against Humanity” set out with the title to wind-up the easily offended.
Having said that, it is a very enjoyable boardgame. It’s a social deduction game, which means that it’s most about lying. Set in the Weimar Republic in the early 1930s, no knowledge of German politics is needed. Indeed, the game could easily be retooled as “Secret Voldemort” or “Secret Trump”.
One player becomes (secretly) Hitler, and with another (secret) fascist henchman/woman, both with the objective of getting Hitler into the position of chancellor. The other players, who make up the majority of players (you need a five player minimum), are all liberals battling to keep Hitler out.
Each player takes a turn as the rotating president of the republic, selecting which laws (liberal or fascist) to pass and appointing a chancellor at each turn, whilst trying to deduce which player is not really a declared liberal but actually a secret fascist.
It sounds complicated, but once up and running it’s actually quite straightforward. As it progresses players get access to more tools to identify members of the fascist party (or definitely rule non-fascists out), and even attempt to assassinate Hitler before he gets to power (or accidentally kill a fellow liberal). The real devilment is when the fascists, if they’re smart, start making false accusations about others, or even riskily voting for liberal policies to throw others off the scent. I was assassinated by a fascist who pretended I was a fascist. I wasn’t.