It was out in the mid to late 90's.
It was basically a child scare/adventure game - at least I found it scary/weird.
You played a young kid with glasses, who had been left home alone and was easily frightened. You fall into this nightmare world, full of ghouls, black cats, witches and devils.
There was a toilet level where you char was afraid of being swallowed by the seat.
There was a school level where you were picked on by these make believe bullies and various things happened.

http://en.wikipedia.org/wiki/Heart_of_Darkness_%28video_game%29