There follows some serious game geekery that resulted from getting a good night's sleep while my sub-conscious did a game postmortem, and a bit of on-line research. If you are not interested in the game, you have been warned.
1) I have seen some discussion on order of play when multiple people are assigned to the same room. We played that all entered together, and then departed singly (if possible). Others have played that each player enters and leaves singly (again, if possible). I would like to see the actual rule. The publisher does not seem to have an FAQ.
2) When played among hard core gamers, the "scare the next person who enters to break the haunt" cards are nearly unresolvable. Players should probably be advised to live in a state of perpetual terror, so that if someone tries to scare them, they are scared.
3) I thought I heard someone say that each player can only draw one card per turn from the Charm Circle, but I have seen comments elsewhere that imply there is no such limit. Again, I would like to see the actual rule as it makes a significant difference (see below).
4) There is NO penalty for having Demon Marks in the Charm Circle until the end of the game; there is no advantage to having Seal Cards in the Charm Circle until the end of the game. Since breaking curses generally involves discarding random cards from the Charm Circle, the best policy is to have nothing but Demon Marks in the Charm Circle until late in the game. It's trickier with a one card draw limit, but otherwise, on the last turn, everyone can throw Seals into the circle and pick up Demon Marks; if everyone has a personal score of -4, and there are enough seals in the Circle, it's a win. (Of course, if the last leader is secretly possessed, and prevents people from drawing the relevant cards, things will go REALLY badly.)