So, a Big Thing is that the nature of the game is that the tragedy has already happened once, and that’s why they know to loop in the first place.

So, they do know, before anything begins, the key players. They just don’t know which archetypal cards are the key players, with the exception of the victim, and why she was killed. So, they know that there’s an assassin, but is the assassin the business man? The police officer? The male student? I can’t remember if the serial killer is revealed out of the gate, but given that the assassin needs more to happen then simply being alone with the student, that knowledge is enough for the players to immediately realize that the shrine maiden is a serial killer. 

Since they do get a reference sheet telling them what each role does, it’s a big hint when certain powers trigger. There are still a lot of moving pieces, but they are given tools to figure things out very quickly if they just keep the key players in mind, and observe what happens. It’s basically a fluid logic puzzle.

But yeah, I had to run it a few times before it really clicked that the players are supposed to have a certain amount of information at the outset. A lot of the key players are common knowledge, and the goals are also common knowledge.