Oh! I was just reminded of another tactic for horror games: making the players do things that they know should be bad ideas. A very good example of this would be from the game Silent Hill 2. Early in the game, the player comes across a section where they have to have their character stick his arm all the way into a hole in the wall to grab a key. There's no way to know what the hole leads to or what else is in it. No person in their right mind would want to do this, but it needs doing so as to progress at all.



There are lots of opportunities to pull this kind of stunt. Stick a necessary item into a vat of steaming liquid. Put the players in a corridor where the wiring, dead at the start, could come to life at any moment. Make them walk through a room full of empty space suits that nonetheless seem to be standing like there are people inside them.

Oh, and one important tip: make sure that you lead into this in such a way that the players know they are willingly making this decision. Put the power in their hands to say "nope", but make the alternative worse. I like to give mine at least three options, each bad, but progressively less desirable the further they go from the "intended" action. (This is not something I do in adventure games, but a lot of horror inherently comes with a sense of powerlessness.)

What system are you using for this, by the way?