- Accidental Innuendo: English speakers may have to be forgiven for initially assuming these books are satirical or even pornographic based on the name of the protagonist. It really doesn't help that the Snowman film actually pronounces it as "hole" rather than the proper "ho-lay."
- Captain Obvious Reveal: In Phantom, it doesn't come as much of a surprise that Cato is Dubai. His recurring appearances and the way he speaks to Harry suggest that he's a character who will be important later. Him being Gusto's father is also easy enough to guess because Gusto constantly addresses his father in his narration hinting at his significance, and it's noted that Dubai seems unusually fond and trusting of him.
- Critical Research Failure: A plot point in The Redbreast involves a character on trial in South Africa and threatened with execution, and at the end he is sentenced to death. The problem is that South Africa had abolished the death penalty well before 2000, when the novel takes place.
- Darkness-Induced Audience Apathy: It can be hard to care about following the series when everything just seems to get progressively worse with each book (with some exceptions), and nearly every case Harry solves can feel like a Pyrrhic Victory, given how many people die or suffer by the end. It says something that if Harry actually had ''died'' at the end of ''Phantom'' then the series might have still been lighter, given what happens to him and his supporting cast in the subsequent three novels.
- Ensemble Dark Horse: Harry's second protege, Beate Lonn, doesn't appear until the fourth book, but is a well-loved character by the fandom.
- Growing the Beard: The Bat and Cockroaches are not particularly highly regarded, as they suffer from a great deal of Early Installment Weirdness and Jo Nesbo was still clearly finding his feet as a writer. It is the third book, The Redbreast, which was the first that was set in Scandinavia, where Nesbo truly comes into his own, and the series vastly improves in quality from there.
- Nightmare Fuel: Many chapters in The Snowman are quite unsettling to read, as the book has a much bigger focus on horror elements compared to the previous novels. The killer's presence is totally dehumanized by the prose, presenting them as more of an inhuman monster or force of nature than a person.
- Iron Woobie: Harry, big time — especially in the last few books.
- Values Resonance: The character of Tom Waller, a corrupt police officer who's described as having cryptofascist views, supplying guns to neo-nazis in an illegal smuggling operation, and who takes sadistic pleasure in victimizing other people, feels increasingly relevant in an age where police brutality and corruption are starting to become far more scrutinized.
YMMV / Harry Hole