Tried to run John Wick's Schauermarchen last weekend with Rocky and our friend Mahar, but sadly things weren't moving in the direction I wanted. While both were nicely feeling the growing tension and the implacable atmosphere of horror, the game just wasn't panning out as I had hoped.
1) No distractions
For a horror game to succeed there should be absolutely NO distractions. No laptop running on the side for players to check their social networks. No snacks on the table. Maybe even no larger drinks that obstruct the view. It won't help either to have food delivered during the game. Or friends text you while you run it.
Horror games have a need to maintain a delicate balance of fear and fun. Too much fear, your players may end up going all defensive and stop wanting to be afraid. They'll turn hero at every turn, even if there's no reason to. They'll act like McGuyver going against Sadako, rather than embrace certain horror tropes or finding ways to fight the horror without leaving the genre. Or worse, they go very defensive and start throwing out humor to calm themselves down. Gory descriptions get humorous replies instead of disgust. Dying non-playing characters are reacted to with, "At least it wasn't me" rather than a moment of shock.
2) No out-of-character moments
Since building tension and emotional reactions are so paramount in a horror game, players need to stay in character as much as possible. This doesn't mean they don't have a character sheet or refer to game stats or systems. That would make gaming very very difficult save for when you're playing with mature, long-term gamers. But this does mean limiting any inter-player conversations to happen ONLY in character.
The basic reason for this is to help support #1. Kinda pointless to grow the tension of how the vampire is slowly approaching your paralyzed body when the two other players whose turns aren't up yet are whispering about the latest Lady Gaga video. Likewise, it doesn't help feed the fear if as the Storyteller narrates how your character is dangling from the window's edge if you then turn to the player beside you and remind them, "Don't forget to use that spell to heal me, okay?
Lock any interactions between them to be "in character" only. A large morsel of what makes horror work is the feeling you are separated or isolated or trapped from being in the safe company of others. In a role-playing game, unless you have enough room (and patience) to have players isolated in different rooms, you're most likely having them all sitting in a circle or around a table. So the isolation is best pushed in how they can interact. To the very least, it will force the players to think, "Oh gosh I so HOPE he...." which in itself adds more to the tension your game will want to cultivate.
3) No sickness
Considering how much I love gaming, I pushed for the session to continue even if I was nursing a sore throat from the previous night of debauchery. (I was screaming my tonsils off as I cheered for a friend who was dancing with drag queens, but that's another story for another day.) Part of me, of course, humorously thought "the bad voice should be okay... its horror anyway." But instead, it had me having to clear my throat in the most inconvenient times. Kinda annoying and disrupting to describe how a grinning man with meat hooks is slowly walking towards you if you end up coughing, clearing your throat and spitting out phlegm between phrases.
As much as it may be common sense not to game when not feeling well, I have to admit it will be something I shall force myself to remember.
4) No second thoughts
If you're running a real horror game, be sure you have players who are definitely interested in playing in one. Excusable as it may be for first timers, the last thing you want is players who mid-game decide, "Uh can we stop. I want to play something more super heroic instead." Remember, playing a real horror game is not about playing something "more real on role-playing than others" or something "more mature than most games." Almost any genre can be approached more maturely. Or can emphasize more on roleplaying.
Horror is a genre. Like science fiction. Like fantasy. Like Military.
And like all genres, they can even be mixed up to create even more awesome games.
But yeah, the players shouldn't have any second thoughts. To the least, if the game seems far darker than they expected, they can all a time out or cancel the game. But with players who definitely like horror, this shouldn't even happen at all. Because those players know it is a commonly accepted trope to have a character die from either something really stupid, "I'll be back..."
So yes, in the future, if I ever opt to run any real horror games, and not games with a touch of horror, I will require my players to be truly willing to embrace that genre. I don't expect all players to instantly be ready for it, but I do want players to let me know they are playing such a game because they like the feel of getting scared, the thrill of going against the unknown, and the knowledge later on, the game ends, and they're all still safe. And satisfied.