Las Vegas Bloodbath (1989)
The movie centers around a man named Sam Butler,who after finding that his wife Ruth has been cheating on her; kills Ruth and her lover and takes to the streets of Las Vegas (with Ruth's severed head mind you). After the double murder, Sam distrust and hate towards women comes forward after the murder of a prostitute and him eventually stalking a group of women at a baby shower for the remainder of the movie. It's this scene that takes up much of the movie, where we see the women eating pizza, playing truth or dare and watching footage of them hot oil wrestling that had been on the news.
After what seems like 30+ minutes, Sam barges into the house and kills the women one by one, after talking to them about how Ruth betrayed him and the anger he feels. I guess the purpose of those scenes is to cause the viewer to feel bad for Sam and that he was pushed to the point of madness. The most memorable of these killings is the death of the pregnant woman,who has the fetus ripped out of her. After one of the murders, one of the women attempt to escape,which alerts the attention of a neighbor(?) who is soon killed by Sam. After the last kill, a cop enters the house and finds the "blood bath" upstairs. Sam is sitting in a bathtub, filled with hot oil and severed body parts (the extracted fetus is also in this scene). Sam promptly shoots the cop and has one last monologue before staring into the camera,when the credits start to roll. (IMDB Illyngophobia)