What I got: a largely episodic slapstick comedy.
Somehow I don't think the brutal murders and cheerful slapstick comedy go together very well. It is like they are trying to fit two different shows into one, and the end result feels like an incohesive mess. For instance, the characters may be investigating a serial killer who murders women in a particularly brutal way. Then they proceed to goof around and act in wacky ways around the corpse. How am I supposed to feel here? Amused? Sad? With the tone doing 180-degree turns within seconds, who knows?
Not every case is equally savage, but the comedy usually still doesn't work. Why? Because it is too simple and repetitive. The same jokes are repeated over and over again until they are run into the ground. They were obvious enough the first time; they are even more so on the twentieth. Often they are character quirks that appear like clockwork whenever particular characters appear on-screen. The comedy is also very conventional. It doesn't challenge any established norms. It loyally adheres to the long-standing model of slapstick in its most blatant and obvious form, shouting at the audience with a megaphone: "This is a joke! Get it?" Yes, I get it because I have seen it before so many times.
It doesn't help that the show has adopted a heavily episodic style with unrelated cases, random villains of the week, and significant pacing problems. It becomes very difficult to care about anything that is taking place on-screen. Sure, let's have a mystery show that is usually episodic. How will that work out? I'll tell you how. I won't care about the victim, the culprit, or any of the random bystanders. Besides, the mystery isn't much of a mystery when we know barely anything about these one-episode wonders. If you like drafting theories of who did it and why, there isn't really much incentive or even enough clues for that matter. Sometimes the culprit only appears near the end of the episode. Yes, there is an overarching plot, but it moves along slowly and with inconsistent pacing.
Here is what an episode might look like. First, some crimes are happening: murder, theft, etc. Oh well, time for people to act in a wacky way, wearing silly clothes, falling over, throwing objects, comically chasing each other for far too long, and blushing at the mere sight of girls. Then back to the murders. But enough of that, let's have people get sexually harassed. Then we go through the facts of the case in the form of... traditional Japanese entertainment? What? Looks like we caught the villain of the week. Then onwards to the next episode with a mostly unrelated case but the same formula. Repeat the same process.
This has been done to death. It has been run into the ground. There is only so much you can do with this repetitive slapstick comedy. Imagine a circus that visits your town every week. It seems flashy at first, but then you realize that every week the clowns, the animals, and the trapeze artists perform the same tricks. Every single week. How many times would you visit the place? This also easily grinds the pacing to a halt. Okay, so there are some differences between episodes. For instance, there is the gangster who makes ludicrous poses and speaks like a madman in every situation. There is also a bath house episode that features Sherlock only wearing a censor bar and a bunch of people in animal masks because... I don't know. Maybe it is some Japanese cultural reference that is meant to be funny.
The one-episode characters are largely forgettable, but the regular cast isn't much better. Sherlock solves cases with semi-blind guesses that happen to be correct. He perfectly guesses the motives of the culprits based on insufficient evidence and profiles them based on superficial features. I suppose he is prone to this in the original novels too, but it goes even further here because most of the cases are so short and there is so little evidence available.
Speaking of Japanese culture, Sherlock delivers case summaries with rakugo, a form of traditional Japanese entertainment. The show treats this as though it is funny, but the punch-lines are simply that some of the characters in the presentation (who are distinct from the "real-world" characters in the show) are dumber than others and slower to figure the case out. This is apparently funny because... I don't know. Misconceptions can be funny, but they need to be constructed in a wittier way than "ha ha ha, you don't get the case" and then proceeding to explain the case. It also doesn't help that it is so random. Sherlock is artificially presenting random characters in an in-universe performance that deals with a case about other random characters who only appear in a single episode. Now, I am the first to admit that I am not the foremost expert in rakugo, but based on my layman knowledge it is usually supposed to be funny. Maybe I am not exactly the target audience here.
The show also features other detectives, but they mostly exist to be Sherlock's foils that lose to him over and over again. And they also exist for character quirks and related jokes, of course. The neat freak detective is obsessed about cleaning and feels insecure when women are around. The former mafia thug detective is all brawn and no brain and is desperate for any attention from women. Etc. Mrs Hudson owns a bar where the detectives hang out. She happens to be a trans woman who acts in a flamboyant, over-the-top manner and sexually harasses people. (The trans characters in the show are usually very stereotypical, and the show seems to assume that they are either inherently funny or weird in some allegedly interesting way.) Watson is mostly a comic relief and exists to make Sherlock look smarter. (I suppose the latter part is loyal to the original novels.) Lestrade is even more of a walking joke and barely appears. Moriarty is a high school kid who is friends with Sherlock and slow to develop. Jack the Ripper is mostly not comic relief, but being a typical evil, brutal serial killer isn't any better. Irene Adler is one of the better characters by being competent but not over-the-top ridiculous, though she is used for generic, predictable fanservice jokes sometimes.
Even generally speaking, so many characters in this act as though they are horny 24/7. See a girl? Instant blush. Speaking with a girl? Awkward, over-the-top reactions with mumbling and arms flailing. Or even better, literally getting a hard on. If you have seen anime or fiction in general, you have probably seen these jokes before, maybe hundreds of times. I don't mind a fresh take on Sherlock Holmes, but not if it means reducing most of the cast into generic comic relief. It is fine to be comedic, but it shouldn't be as lazy as this.
It wouldn't have to be this way. If they wanted to make more of an effort, they could have gone in a number of directions. One idea with potential would be black comedy that involves morally questionable topics. To clarify a bit, there is a difference between applying black comedy and sprinkling unrelated light-hearted comedy among serious events. Kabukichou Sherlock does the latter. It features murders and other crimes that are treated as serious while throwing in unrelated slapstick comedy. I would have preferred deriving laughter from the potentially evil actions themselves. Crimes can be funny, but they have to be committed for a suitable reason and with sufficient build-up. For instance, you could have a comedic sociopath who is doing it for reasons that are at least remotely relatable but still lacks a firm moral compass. Bonus points if he is relatively chill about it. Then you point out that the action is kind of dodgy without actually sounding preachy about it. But here we usually have generic scumbag culprits with thirty seconds of characterization or complete monsters that are portrayed in the most over-the-top disgusting, ugly way imaginable. The rest of the culprits have motives that are flimsy, nonsensical, or unrelatable.
By the way, the show feels like there is a need to repeat over and over again how the eastern part of the city (where the detectives are based) is a city of neon lights, chaos, and endless crimes. A few times would have sufficed. Speaking of the city, there is apparently a Berlin wall between the western and eastern side, and passage through it is tightly regulated. When did we suddenly cross the Iron Curtain? I think we deserve more of an explanation here. This wall thing could actually provide material for jokes if used right, but of course they do not even try. (Or if they did, it is so out of line with their usual approach to comedy that my mind did not register it.)
I guess this show just wasn't meant for me. The jokes don't land or deliver. It gives me the impression that I am not in the target audience at all, and that is probably the case, but the marketing should have been more honest then. I wasn't expecting jaw-dropping mysteries, but I was expecting something with a bit more effort. Even when there is mystery, it falls flat because it is impossible to care about the outcome, the deductions are more like guesses, the constant tone swings ruin the mood, or the culprit is driven by nonsensical motives. They should have called this a slapstick comedy from the start, though it would have still been ruined by the inconsistent tone and the sheer repetitiveness.
