Miscellany: Running a "Call of Cthulhu Campaign"

I'm going to start GMing my first "Call of Cthulhu" campaign this fall, and I've reflected on it a bit. Being a "Call of Cthulhu" game master (or, as the game calls it, a "Keeper of Arcane Lore") can be a difficult proposition. Unlike other RPGs, CoC is set in the real world, which means you can't just invent locations and people wholesale. If the investigators are going to Peru in 1923, you damn well better research what Peru was like in the 1920s. This sort of campaign preparation might seem like a lot of work, but it can also be a lot of fun.

Another problem facing CoC keepers is the fact that almost every encounter in the game can turn deadly. Ordinary thugs armed with crowbars can quickly overwhelm the average party, and it gets even worse when you throw in the near-immortal monsters of the Cthulhu Mythos. Additionally, since investigators never gain hit points and typically lose Sanity every time they're played, an experienced investigator is often no stronger than a brand-new character. It's very hard balancing a campaign when the protagonists can actually get easier to slay as time progresses.

The final issue that I believe is most vexing is the creation of a proper atmosphere. CoC includes some LARP-lite elements. For example, the game manual suggests playing sinister or period music to set the mood, as well as creating fake telegrams, letters, and other documents for the players to read while playing the game. I'm not sure things like this help the game to be scary, but they sure sound cool to do.