At the end of Dead Roads, there was the AP overview that called the AP Survival Horror. Now this will no doubt bring up thoughts of Resident Evil Silent Hill with the hordes of monsters and scavenging ammo and of course, alien logic puzzles, but those still let the player be empowered via firepower when the rifles, grenade launchers and chainsaws be found. Another type of horror series are the Amnesia and SOMA games.
In these games, fighting is not possible and it does kind of get weird with the 'Turn around and look at the wall' mechanic of not losing your mind but it is pure stealth and distraction. Which might be a good option for this AP but there is the problem of 'Boss Fights'. Pretty much every McGuffin is held by a monster that must be fought in the classic manner and I think it would require a lot of reworking to allow the PCs to say, stick a holy wrench into the Festering Maw and run like heck before it explodes while ghouls and vampires how at their heels.
Perhaps this is something that can be more of an option in some APs? Sneak in through the air vent and disable the tractor beam so your ship can get away hile one stays behind to fight the Dark Lord.