Kind of an untapped genre, but after playing homeword:cataclysm I'm convinced that this is a type of game that has some pretty good potential. Just have to do the usual horror things: creepy music, art syle, good acting, and on top of that burden the player by making them responsible for the lives of a large number of difficult to replace troops/ships etc. Then equipp said troops with stun rods and tell them to go and poke a bunch of unknown organisms with the stick, and enjoy the ensuing horror and carnage.
Edit: I suppose x-com might fit the description, but I don't know much about those games.