A bit disappointed
I consider myself to be a big Bergman fan (specifically the "Trilogy" and Persona), but after finally seeing this movie I found myself a bit disappointed by it. First off, other than having read that it was a horror film, I really didn't feel any sort of fear until the scene with the young boy. Even the scenes at the first party I just found more bizarre than eerie, and by the end I just assumed he was going mad, and so I didn't really feel any fear at that point either (and even if he wasn't going mad, it felt so contrived that I had a hard time taking the fear aspect seriously).
My other drawback was that I had a hard time grasping the theme of this movie. It definitely overlaps with Persona, but I found there to be less thematic development, and more emphasis on trying to make it feel eerie.
Maybe Bergman's ideas of horror just isn't really suited to my tastes, or maybe I just don't relate well enough to this particular approach to grab my interests, but I really felt as though this movie lacked the intense clarity of mood and theme that I love about Bergman.