Phantasmagoria 2 is one of my all-time favourites, although I was a bit let down by both of the alternative endings. (I've never yet played P1.) My personal favourite scene is near the beginning, when
Spoiler:Curtis is at the computer and is struck by an invisible force
That is really shocking in the quick make-you-jump sense, and then more deeply frightening as you realise
Spoiler:it's got to be real -- it drew blood and Trevor can see the injury
Thinking about it still makes the hairs prickle at the back of my neck.
The reconstruction of
Spoiler:Bob's murder in the office
is a scene I'll probably never forget, either. Not entirely in the good sense.
The infamous "alien machine" puzzle near the end is not as difficult as some people make it out to be, if you approach it with strict logic and the spirit of trial and error. Figure out what each part does individually, then work out how to put them together in the sequence you need. It takes time and a little perseverance, but it's not a mindbender.