Halls of the Pale Widow. I believe it's more like a tech demo though.
Run away from scary woman. Get caught and stabbed. Unlock sex. Get caught, sexed and stabbed. Unlock correction and sex her back if you find all the mcguffins. Pretty simple, but grind is shit, so use CE to unlock everything.
Dev is working on a full game with different ghosts/monster girls if I'm not wrong.