Iris is a meek, mousy woman of maybe thirty years of age. She works a boring, mindless job on the assembly line of a match factory. She comes home to her mother and stepfather's shabby little apartment, where she is expected to do the cooking and the dishwashing. She sleeps on a couch, and she pays them rent. When she goes out for a bit of fun, namely to a dance hall, she's the only woman there who isn't asked to dance.
Iris treats herself to a pretty floral dress and goes clubbing. She meets a man, Aarne, who takes her home for sex. Iris is infatuated, but what she doesn't know is that Aarne thinks she's a prostitute. Disappointments and trauma pile on top of each other, until finally Iris snaps.
- Beware the Quiet Ones: Iris. Meek, shy, hardly ever talks, beaten down by life. Until she snaps and murders four people over the course of a single evening, that is.
- Dances and Balls: Iris's depressing life gets even more depressing when she goes to a dance hall and no one asks her to dance. She has enough time to drink five bottles of soda before she gives up and goes home.
- Death Glare: Iris shoots one at Aarne after he leaves to get ice for her drink. This is followed by her pouring the rat poison in his drink.
- Establishing Character Moment: We learn all we need to know about Iris's mother and stepfather when, upon finding out that Iris bought a party dress, her stepfather slaps her and her mother doesn't raise a peep of protest.
- Good Smoking, Evil Smoking: About 20 minutes before the end, having had all her dreams shattered, Iris lights up a cigarette for the first time. This is immediately followed by her going on a murder spree.
- Gory Discretion Shot: We don't see the deaths of any of Iris's victims. The film cuts away as Aarne is drinking his poisoned drink. After Iris serves her mother and stepfather poisoned vodka she goes into the living room and listens to music for a little while. She then goes into the next room to make sure they're dead, but the camera stays on Iris and never shows mom and stepdad. (Rat poison is a bad way to go. Vomiting and blood.)
- Ironic Juxtaposition: Starts with a long introductory scene showing how a log becomes a bunch of matches, one step at a time, a sequence that could have come from How It's Made. The sequence ends with Iris checking labels on boxes, and then the film follows her home—changing clothes, clocking out, cooking dinner—in a manner that suggests her life is just as rote and machine-like as the machines at the factory.
- ISO-Standard Urban Groceries: When Iris meets her mother at the front door near the end, Mom is carrying a brown bag with some greens sticking up out of it.
- Leave the Camera Running: There is very little camera movement in this movie; most of it is a series of static shots. The last three minutes or so are a single static shot that shows Iris at work, where she's arrested; the camera continues to run for a while after the cops have escorted her out. Really the only camera effect in the film is the zoom in on Iris's face when she finds out she's pregnant. The near-total lack of camera movement in the rest of the movie makes that shot quite dramatic.
- Morning Sickness: How Iris finds out that Aarne knocked her up.
- Offscreen Crash: Iris walks out of frame. While the camera continues to point at a random building, there's the sound of a crash. The film then cuts to Iris in the hospital, having lost her baby after she was hit by a car.
- One-Person Birthday Party: For her birthday, Iris gets one present, a book from her mother. She then goes out and has one piece of cake. Alone.
- Roaring Rampage of Revenge: Over the last 20 minutes of the movie Iris murders Aarne, her mother, her stepfather, and some total stranger who made a pass at her at the bar.
- Silence Is Golden: Very little dialogue. Iris has two lines of dialogue over the first 25 minutes of the movie. Her stepfather has two lines for the entire film. Long stretches pass in silence. In fact, The Match Factory Girl easily could have been made as a silent movie.
- Voiceover Letter: Probably at least half of Iris's dialogue for the whole movie comes when she writes the Voiceover Letter telling Aarne that she's pregnant and she hopes he'll help her raise the baby.
- Would Hit a Girl: Iris's bastard of a stepfather slaps her and calls her a whore when he and her mother find out that Iris bought a party dress.