In the striking death scene, the camera remained fixed on his face as he fell backwards down the full flight of stairs, and then was stabbed repeatedly with the upraised knife at the foot of the stairs.
It masterfully told the back-story of how the monstrous killer had a very troubled and abused childhood with a sadistic father who filmed him for his studies on the physiology of fear in children.
Over time, it has been critically re-evaluated and vindicated, and is now universally regarded as a masterpiece of psychological terror.
In fact, their string of daily jogs became a healthy activity for the two, with built-in social distancing from others.
The movie was praised for its profanity, which aptly fits in for an adult movie, along with the gag comedy moments that it boasts of.
The film also won nine awards at the in 2015, including and 10 awards at the , including Best Film.