So how do you make the risks terrifying without a high character turnover? Well, there’s a number of ways:
It doesn’t have to mean death. If someone falls to a monster and the others run, you don’t necessarily have to slaughter the character then and there. What if they woke up with their hand gnawed to a bloody stump? Or in hospital with some mystery stitches? Or the monster drags them to its lair and they wake up on 1 hit point with chittering larvae creeping towards them? There’s a bunch of ways to continue the character’s story while reducing the death rate.
Signal the difficulty level. This is especially important when running an action horror game. Okay so the players have mowed through six zombies … give them enough hints that the monster crying in the corner is a little more deadly than what they’re used to.
Alternatives to combat. If you force them to fight everything they meet in a high-damage game with slow healing times, they’re likely to die often. So allow them to avoid a fight by luring monsters elsewhere, sneaking past them or using the environment to trap or kill the monsters for them.
The monster doesn’t want to kill them yet. Maybe the serial killer wants to torment the player character, now they’ve seen their face, rather than kill them outright. Maybe the monster enjoys the thrill of the chase and hurts them but leaves them to crawl away and if they’re clever perhaps they’ll survive.
Environment can help. Naturally it’s best to avoid throwing in a deus ex machina, but if you tie it to dice rolls or give player characters meaningful choices to make, the environment can make a great ally. Maybe there’s a heavy shelving unit they could tip over into the monster’s way or a large door they could slam. Maybe they could set up an electrical trap using cords and a pool of water.
Let it drop but don’t let it die. Some horrific threats might drop when shot up but won’t die no matter what they do. This way the creature doesn’t have to deal a lot of damage while still being scary because it will win any battle of attrition. This lowers the frequency of death but increases the sense of inevitability.
Build the likelihood of death slowly. You can leave them convinced they could die at any moment, but actually weight the real odds of death toward the conclusion. If most of the party (or even all of them!) die at the end, that can be a real satisfying conclusion for a horror game and you don’t need to worry about them having to introduce random new characters midway through.
Well, those are a fair few ideas at least. You can find more in our 10 Balancing Acts of Horror.