First and foremost, I am surprised this show is still getting sequels given how poorly it was received even in Japan. The show's premise is bizarre and borderline inappropriate for a kodomo show. The main protagonist, Butt Detective, is a literal anthropomorphic butt who investigates crimes by sniffing out hints and farting on criminals. This concept is not only juvenile but also crass, and it leaves a bad smell in one's nose from the get-go, and it doesn't help when the main antagonist is a literal piece of shit.

Spoiler, click to view

As for art, with the exception of a few beautiful static landscapes, the animation and character designs are lacklustre and unappealing. The show's visual aesthetic is heavily reliant on simplistic, pastel-colored shapes and characters that resemble elementary school doodles rather than professionally drawn anime characters. This design choice may be acceptable for children, but it does not cater to the tastes of the main anime-watching demographic.

The show's humour also falls flat, relying on cheap puns and toilet humour that will only appeal to the lowest common denominator. The jokes are repetitive and quickly become tiresome, further detracting from the viewing experience; I got bored quickly after watching only two episodes. The dialogue is stilted and poorly written, with characters often stating the obvious and making unnecessary comments that do not add to the story or the development of their personalities.

The show's pacing is also an issue, with episodes feeling disjointed and lacking in cohesion due to the episode being paused for some silly children puzzles, I felt like watching cutscenes or a gameplay of a cheaply made mobile video game. The narrative is frequently meandering, with little sense of direction or purpose; it has an episodic format but is also aimless. Character development is also hampered by the show's episodic nature, with characters remaining one-dimensional and stagnant throughout the series.

Furthermore, the show's sound design and music are subpar, with forgettable and unremarkable background music and sound effects that do not enhance the viewing experience. The voice acting is also unimpressive, with characters delivering their lines in a monotone and uninspired manner.

The premise, unappealing animation, and lacklustre writing make Butt Detective a bizarre and borderline offensive joke that is tedious and forgettable to watch. Definitely ignore it, unless you're curious about how bad it is.