That's a tough question, Becky. The two games are so dissimilar in look and atmosphere. Shivers is VERY colorful, artistically, which is actually one of the things I liked about it, and yet it maintains a consistently spooky feel to it. Lots of puzzling involved, and a very nonlinear game. That's another thing about the game that I found appealing, as, if you are stuck on something, you can just move on to something else.
And I realize I haven't answered your question. For me, the words "terror" and "horror" don't apply to Shivers. It's just....quietly unsettling throughout. I've never played anything quite like it.