Everyone is assigned a role, either Liberal, Fascist, or Secret Hitler. In a group, it's about half+1 Liberals, with the rest Fascists, and one Secret Hitler. At the start, everyone closes their eyes, and then the Fascists can open their eyes and identify each other. Secret Hitler keeps his eyes closed, but indicates who he is with a Thumbs-Up. Hitler is a fascist, but doesn't know who in the government is secretly trying to help him. Everyone closes their eyes and the game begins.
One person is randomly selected President. They nominate a Chancellor. Everyone in the group, the government, votes Ja! or Nein! on the Chancellor. If the vote fails, the role of President rotates to the left and the process starts again. If the vote succeeds, the government is formed and the pair goes to work. The President selects three policy cards from a deck. Policy cards simply read either "Liberal" or "Fascist". The President discards one card of his choice, and passes the remaining two to his Chancellor. The Chancellor then enacts one policy by playing it to the board in the middle of the table. The deck is about 2/3rds Fascist cards.
If enough Liberal policies go into effect, about 5, the Liberals win.
If enough Fascist policies go into effect, about 6, the Fascists win.
When each Fascist policy is enacted, it gives the President a one-turn power of authority to perform a given game action. The first one that goes into effect allows the current president to check the Liberal/Fascist alignment of another player. Another one allows him to pass the next presidency to someone else out of turn. Both the fourth and fifth policies allow him to "kill" another player and remove them from the game.
If 3 Fascist policies are enacted, another rule takes effect... from that point on, if the President ever nominates Secret Hitler as Chancellor, and the vote succeeds to form the government, the Fascists instantly win.
The instant-win condition for the Liberals is if one of them is President when the Fascist power to kill is enacted, and the Liberals manage to kill Secret Hitler.
...anyway, every move provides some area of suspicion, and enough added together make it fun to either try and guess what's going on, or, pull one over on the Liberals to get Hitler into power. Did the Chancellor have any choice in enacting that fascist policy? Did so-and-so vote against the Chancellor because he's a fascist? Has Hitler found his allies in the government?
It goes fast enough you can play 3 or 4 games in a row without getting bored, though keeping track of who betrayed who, and when, can get cloudy after several runs. All-in-all, fun game.