Frictional's next game...

[Swarms]

Yeah why not, scrap the werewolves and the vampires, instead imagine old abandoned castle, you are the reporter in search of a scoop, the castle have been used by the nazis for experiments, some nasty ones. So you walk inside, and fall through the rotten floor and are trapped inside the castle with all kinds of nasty creatures. Puzzles like Penumbra ones would need to be solved to get out.
...

Imagine a room where there is pitchblack, the only source of light is the flash of your camera, and suddenly a monster appears, you can avoid it by flashing ones every 2 second, damn that would be scary.