Duplex is a black humour comedy about life with roommates

Duplex is a 2003 black comedy film directed by Danny DeVito and starring Ben Stiller and Drew Barrymore. This film is a funny story about a young couple, Alex and Nancy, who buy a wonderful duplex in New York City, but run into unexpected problems with their elderly tenant named Mrs Connelly on the top floor. She sends them both out on countless errands, keeps them up all night (every night), forces them to quit their jobs, and decreases the value of the property every day.
Since they can't get rid of the nice old lady because of rent control, Alex and Nancy try to get her to leave the flat, eventually resorting to less and less friendly methods.... and becoming more and more clumsy as they try.

Let's break down what's noteworthy from a storytelling perspective in this albeit uncomplicated, but very funny and sweet film from the early 2000s.

The main themes of the film are
Clash with neighbours
One of the key themes of the film is interaction with your neighbours and the problems that can arise because of this. "Duplex" shows that being a neighbour can be difficult and even disruptive to your personal life, especially if your neighbours turn out to be a nuisance or simply act disrespectful to your space.
Stress and relationships
The film also touches on the theme of how stress and extreme circumstances can affect relationships between loved ones. The pressure caused by conflicts with tenants severely tests Alex and Nancy's relationship, revealing their strengths and weaknesses.
Humour and satire
"Duplex" is also known for its comedic elements and satire. The film uses black humour to highlight the absurdity of the situation and the madness in which the main characters are immersed. In fact, the entire film is one big hyperbole designed to give us a good laugh.
Acting and directing

Ben Stiller and Drew Barrymore are excellent in their roles as Alex and Nancy, conveying the emotional and physical comicality of their characters.

Eileen Essel, playing the role of the old lady, also accentuate their characters perfectly, making them unpleasant but also vivid and memorable.

Director Danny DeVito skilfully brings chaos and madness to the screen, mixing comedy with elements of black drama.
A few busy storytelling techniques you may not have noticed, but they make the film more interesting
Missis Connelly is both a bitch in sheep's clothing and a Cool Old Lady. Not only is she a high-class slave owner who constantly asks for help, but she's also the widow of an Irish sailor with a parrot and a spear. And at the end of it all, it's revealed!

Alex gets the worst of it - he gets the most unpleasant situations, up to the point where he almost gets shot with a spear thrower. This character is called butt monkey.

The whole film is Cringe Comedy: From the moment they get to the house, such a barrage of misery descends upon them that they readily decide to hire a hitman to kill Mrs Connelly, because as long as she's alive and is the centre of this misery, it's not like any options are going to make it any worse.
"I should write a book about this" - The protagonist attempts to write a book throughout the film and fails miserably, mostly because of his upstairs lodger. At the end of the film, his published novel called "Duplex" is shown, presumably about the events he experienced during the film.

In the UK, the film is called "Our House".

The police are useless (as in most films and TV series) - Every time Alex and Nancy call the police to make a complaint about Mrs Connelly (noise, whatever), Officer Dan arrives and gives them a thrashing for allegedly harassing an infirm old lady.
Technology Goes Forward - Alex had the only copy of the novel on his laptop, so when it was destroyed, he didn't have a backup. With the advent of cloud storage, he could have a copy anywhere he had internet access, and not having a backup wouldn't have been a problem. Oh, and in principle, any prudent and prudent writer usually backs up their work.

"Duplex" is a comedy film that takes a fun and sarcastic look at the issue of neighbourhood relationships, stress and its effect on relationships. The film leaves the audience laughing at the absurdity of the situation and perhaps wondering how they themselves would act in a similar situation. With an excellent cast, well written characters and direction, this film leaves a vivid impression and provides plenty of entertainment.