Okay, so this weekend my buddy Steve ran another session of his Call of Cthulhu game for us. It's set in the late 1920's, in classic style, and started in Canada. Currently the group has made its way to Japan with a cargo of mysterious stone relics which weird creatures from space desperately want for some reason.
While playing it struck me that I've never seen a PC go mad in any Call of Cthulhu game I've ever played. A number have been killed outright, but none suffered any sort of mental conditions. And yet the whole Sanity mechanic in CoC is supposed to be a key "cool" feature of the game. To be fair, several of our current PCs basically started with mental conditions as part of their background (mine included) but that's not at all the same thing. One problem is that most situations only call for a small loss of sanity and most if not all of that can be gained back by defeating things. So nobody really starts down that long slippery slope into the darkness of the mind. Your Sanity point total hovers near your starting maximum pretty much all the time.
Now my friend Bill pointed out that this was because we had only (so far) faced defeatable lesser creatures which only caused small sanity losses, and only if you missed your save. Larger creatures cause losses of bigger chunks and are difficult to impossible to kill. So even if you do survive there will not be any comforting recovery of points because you will not kill it. At best you escape and constantly awaken in the darkness, heart pounding, wondering "What was that noise outside?"
Point taken, but it makes for a very slow game. And is Call of Cthulhu really meant for a long campaign anyway? I would argue that it is not. Yes, you need some build up to create the atmosphere of relative calm specifically so that you can shatter it later. But I think that events really should ramp up rather sharply, with things going from disturbing to serious terror in a relatively short time. The PCs (and players) shouldn't have time to recover. There should be lots of panic and that sense that "we're all gonna die!!!!" And really weird shit should be happening, shit that even the players can't make sense of in the rush of the moment (although there should be good reasons behind it which the survivors might discover later).
And those scenes of raging, flaming chaos should be interspersed with periods where they alternate between desperation, paranoia, and hopelessness. The PCs should be struggling to cope, mentally and physically with what the hell is going on. Their chances should always seem slim to none. Every time they learn more about the threats facing them it should be clear that things are even worse than they thought and their chances of stopping it seem slimmer than ever.
Almost every encounter with indescribable horror should leave them with less sanity than before. A constant downward psychological slope helps add to the pressure. There should be few, if any, chances to regain sanity. And some of those should come with a price, such as taking drugs (possibly exotic ones hard to explain to normal people or the authorities). The Sanity mechanic should probably include levels, say every 15 points, that trigger a permanent worsening with in-game effects. These effects should make it harder and harder to function against the threat and harder to interact smoothly with normal people.
And physical damage for a game like this shouldn't just be hit points. There should be scars, probably obviously weird-looking ones which you can't explain to normal people. Damage during combat should cause impairments, such as having one arm out of commission. There should be a lot of permanent physical damage, although a lot of that can be internal. They get some weird goop on their arm from that tentacle and now the bones are going kind of soft and bendy. The feeling of gradually losing capability in the face of mortal danger helps add to the psychological pressure of combat with things you wish you'd never, ever found out about.