Doom scare-factor doesn't scare me anymore. After finishing it on Veteran a few days ago, I realised - I like the game, but the frequency of demons' random appearances becomes less scary, in fact, it becomes repetitive. Definitely not as scary as I remember it to have been.
Anyway, more to the point; I really hope Doom 4 is properly scary and immersive enough that the scares make me jump from my chair.
Edit: Admittedly - I had moment in Doom 3 that shook me , and that random moment when I jump for something very silly and random.