This is not a satire or a parody, it is a parody of the movie itself, if this makes sense. It starts as a very serious dark thriller and quickly turns into a very fake slasher, with very bad dialogue- that actually turned bad after intentionally dubbing it in English, even though the original dialogue was also in English. That created a very fake feeling and a sterilized sound environment, that spoofs European thrillers from the early 80's. But instead of having actors talking about serious matters, like in most thrillers (for no apparent reason and with no explanation), everyone in Razor is talking about moronic everyday needs, like cooking, sleeping, eating, having sex etc. It's not philosophical or clever, it is just what normal people do. And that is the hidden layer in Razor, why most people are victims and why they don't fight back.
The movie criticizes something else than slasher movies, it is not Scream or Scary Movie. Razor hides a layer of hate against people who spend their weekends somewhere close to nature, together with friends. This probably sounds weird to most of you, because you probably think that such a weekend is fun. And that is why you probably will not understand the humor of Razor. The director tried to make it from the perspective of an alien life form, who tries to understand humans and their habits. Like a predator, that alien life form is convinced that you need to put just the basics inside a movie and to torture people and kill them to have a great body count. The shock value in the beginning and in the end of the movie are there because of lack of filtering, how extreme it is and when you go too far. Incest, sensitive body parts, weird motives, if you really think about it, is actually great fun.
So what is this movie all about? Why spend 75 minutes of your life watching it? The plot is pretty basic, so basic that you can describe it in one single sentence: Friends spend the night in a mansion, they have dinner and sex and someone captures, tortures and kills them one by one during the night. The movie plays with the idea of having such a basic plot, only to focus on how torturing people actually works. The camera focuses only on the victim and his/her reactions, and is mostly close-ups. The movie is a study in reactions, because the actors were tortured up to a certain degree for real. The chains and locks were real, the whip, the electric saw, so what you see is almost real footage of torturing. Having that information, the movie is a different beast, right? It's not snuff, but it is indeed a study in reactions, you can tell when the actor hated the situation and when he or she needed to stop. They were free to express themselves, because they could not really move, so their fear is real. It was scary for most of them and the shootings were done with appointments, like BDSM sessions, it was an extreme experience for all of them. So, if you are willing to watch it, do it with that in mind...