Creepy soundscape and TV visuals

The actual monster is not that scary as we see it only in the book, and in the house in shadow with only partial lighting, but to me this movie is very creepy in its soundscape, like the mother's mentally-addled state between sleeping and waking, the monster sounds, and that sequence with the whispering and voices. Also, the TV side of things is unnerving as well, like the Georges Melies-style dream-like images with monsters and disembodied heads, not to mention later on the horror movie scenes and when the mother sees herself in a window of a murder scene house.

I've heard that this movie used a videogame sound effect for the monster, like a dragon roar or something, but since I didn't know about that, the soundtrack for this movie remains unplagiarised for me.