Very spooky! I felt really tensed playing the game, wondering what's gonna happen after the lights turn off and I was frantically searching for a light switch. The shadow monster spooked me too when I walked into it face to face one time.
I wish it was a little easier to see in the dark and have the monster be a little more visible. I think it's scarier to see the monster coming at you because most of the time, I would be looking for a light switch and then the screen would turn red and that was it. I eventually won because I got lucky with a crate on the first floor, hehe.