Stuff jumping out is not scary. It was like Resident Evil 4 in space.
What makes Amnesia so scary is that you are completely helpless to defend yourself, and you have absolutely no idea what to expect. Dead Space is just walk for it a bit, stuff jumps out, shoot it, kill it, keep walking. It's not really scary when you can just blast through anything in your way.
Dkamm is right, what makes Amnesia scary is the thought of the unknown. You don't know whats around the corner or whats coming up next. When you run out of oil, you get this feeling that theres something right in front of you and you cant see it.
While dead space is just as she said, walk, something jumps out in front of you, shoot, continue.