In terms of production-value the show has proper animation-quality and music, the opening and ending themes being particularly superb. One upside to the directing is how the show dramatizes certain scenes. With many other adaptations based on books, you can sometimes see awkward pauses where there is obviously supposed to be internal monologues. Ranpo Kitan gets around this pet peeve of mine by creating theatre-stages that represent the characters’ internal thoughts, a welcome bit of inspiration. The choice for the designs are however jarring, with mixes of cartoony and edgy scenes.
As a mystery-series it falls flat on its face due to showing too little detective-work, on the contrary it dumps exposition that instantly solves each case in the viewer's lap. On more than one occasion, the mystery will be solved in a rush and the murderer will turn out to be a complete stranger that was never part of the story until that point. This makes it all the harder to make a single guess on your own, hindering immersion.
As a horror-story it has a few redeeming qualities, though few and far in between. While the twisted and dark backdrop exists to give the show a pretty Halloween-wrapping, the presentation is far too cartoonish to provide any real tension or scares. The only area Ranpo Kitan excels in would be its attempts to disgust and shock the audience, turning itself into a freak-show of characters that are meant to entrance and fascinate in how strange they are.
Credit where credit is due, a few side-characters do become fascinating to follow. The problem arises when the majority of the cast act like aliens that contradict every social norm and logical thought-process. The main character is detached and bored with regular life, to the point that seeing horrible things will make him feel happy and alive, which is another trait that makes it hard to take anything that happens seriously. While I personally am not against stark tonal-shifts, you need sympathetic characters that you want to follow through the madness in such cases. In Ranpo Kitan's case the characters just add to the confusion on what the show is actually trying to be.
I could only recommend this to people interested in seeing a trainwreck, as it can be entertaining in that regard. Overall Ranpo Kitan ends up being an annoying and rushed kind of bad, showing potential in some moments but ultimately dropping the ball.
