NSFW: Der Todesking (1989), directed by Jörg Buttgereit

I first saw this in the early 90s. Apparently, it is not available on DVD in the US, but can find in on VHS if you still have a player. The trailer is NSFW.

Synopsis from Wikipedia:

Der Todesking (aka The Death King) is a 1989 German horror film directed by Jörg Buttgereit. This experimental style movie which does not use central characters explores the topic of suicide and violent death in the form of seven episodes, each one attributed to one day of the week. These episodes are enframed by the vision of a human body, slowly rotting during the course of the movie.

Monday A man comes home, phones his boss to resign from his job, writes mysterious letters, cleans his apartment and swallows poison in his bathtub. His death is simultaneous with the death of his fish, the only being that was close to him.

Tuesday A man rents a film in a video store, a movie in which Nazi soldiers are torturing a prisoner in a concentration camp, castrating him and painting a swastika on his breast. When the young man's girlfriend comes home, she yells at him until he shoots her. He then places a picture frame over the place on the wall where her brain matter was splattered. This whole episode is being shown on a TV screen in a room where somebody has been hanged.

Wednesday A man and a girl meet in a park in the pouring rain. The man tells the girl about his disastrous sex life with his wife which led to him killing her. The girl pulls out a gun to kill him, but the man takes it from her and shoots himself.

Thursday A motorway bridge somewhere in Germany, superimposed by the names, ages and occupations of the people who have jumped from it.

Friday A woman, alone in her apartment, is observing a young, seemingly happy couple in the neighbourhood. She spies on them and finds a chain letter in front of her door, urging her to kill herself. Obviously everybody in the house got the letter. She ignores it, eats chocolates and falls asleep, dreaming of surprising her parents when they make love. The camera shows the young couple, dead on their bed.

Saturday A young woman, equipped with a camera and a gun, kills several people in the audience of a rock concert (the front man is played by Die Ärzte drummer Bela B.) and records it on film, until someone kills her.

Sunday A man, alone on his bed, is crying and banging his head over and over, violently against the wall, until he succumbs to brain damage.