Ghouls vs. Humans/YMMV


 * High Octane Nightmare Fuel: The ghouls, obviously. Even if you're one of them, you can still get startled by your teammates or by your own reflection in the mirror.
 * Paranoia Fuel: The Creeper is pretty much invisible while crawling along the ground. And he can follow you for a while, then pop up at any point and literally scare you to death.
 * The Scrappy: The "Santa Claus" class seemed to be highly unpopular, so it was replaced with the Engineer.