I remember being blown away by how intense and visceral the experience was, it probably helped I played it on my uncle's top tier 486 with a great sound system. Whenever I look at screen shots these I'm kind of shocked how pixelated the sprites were, I guess it wasn't a concern at the time.
CRT monitors made things look so much more vivid than on LCD. So when you look at old games today and think «Did it really look this bad and pixelated?», the answer is actually «no».
Doom didn't cause me nightmares as a kid, but when Dead Space got released I bought it, played a bit, then stopped because I didn't enjoy the jump scares at all. And I was an adult. Well made without question, but not for me.