Playing it now, I'm more into the theme - I prefer a fantastical one, but I'm more into the horror concept now than I was back then and approached it thinking I might appreciate it more. I'm not sure it's especially well executed however: looking at it critically it's a bit of a mishmash of Hammer Horror tropes all kind of stuck together...
The series dabbles a lot more with gothic horror as it goes on, but marries it very successfully with the fantasy theme (most of Stephen Hand and Jonathan Green's books, plus a lot of Keith Martin's.)
As a kid the horror ones were by far my favourite - but
even then I didn't really like House of Hell. I'll try and pinpoint why in a few playthrough's time. Maybe the modern-day setting? Maybe because it was too damn hard to be any fun?