The Guardian has posted an article on the resurgence of the sex movie. They start with Knock Knock and go from there. Eli Roth says the following about the film:
“I wanted to make a movie that was very performance-base,d but without the kills and the gore and the blood,” says Roth. “Y’know, I feel that I don’t want to repeat myself, I don’t want to be known – even though I am – for one particular thing. And, as you get older, different things happen. I mean, I’m married now. I thought: ‘There hasn’t been a Fatal Attraction for a modern generation.’ I wanted to make a movie that 20-year-old girls would see and love, and really understand these two girls, and I also wanted a movie that guys in their 40s would see, and married guys would see, and understand Keanu’s position.”
You can read the entire article here.