These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
YMMV: Fist of the North Star
The Manga and its Adaptations:
Anvilicious: The most subtle thing to happen in this series is the movement of Ken's eyebrows, and even those look like caterpillars.
Anti-Climax Boss: Bolge, the final villain of the manga, although cool, is nowhere nearly as memorable as Raoh or Kaioh.
Ass Pull: Quite a few due to the fact that Buronson and Hara wrote the story as they went along. The most obvious being the "UD" mark on Mamiya's shoulder. How come nobody noticed it when she was undressed in front of everyone by Rei? Or how about Raoh and Toki coming to Japan along with an infant Kenshiro as refugees from Shura in Hokuto no Ken 2. Didn't we see the ruins of Raoh and Toki's home village in the original series?
Better Than Canon: Fist of the North Star: Ken's Rage has a "What-If" mode wherein Rei beats Raoh and live happily ever after with Mamiya. It turns out to be a prophetic vision and Rei goes on to meet his intended fate (to die at Raoh's hands) regardless, as he feels that he can't prolong his life at the risk of his friends. Possibly justified, as Shew does manage to die in Rei's Dream Mode and Rei blames himself for it. Or alternatively looking, Rei became inspired with Mamiya in Dream Mode to risk her life for the right cause, fighting against Thouzer's army despite the information that if she rebels she will face death, therefore once he wakes up, he realizes that trying to go down the Dream Mode route would basically be the coward's way out.
Jagi and Toki's Dream Mode stories are also seen in a similar light.
Though a somewhat Downplayed example, Ryuga still tends to be viewed as a neutral figure at worst, despite him fatally wounding Toki and killing many of the man's patients in order to get Ken to fight him.
Ensemble Darkhorse: Despite only appearing in one episode, Mr. Heart has had a place alongside major villains and heroes. He's appeared in the Arc System fighting game, the Xbox360 beat-em-up game, and the 1996 film thanks to his off-the-wall style, even by the show's standards: he's a morbidly obese martial artist whose mighty gut keeps Kenshiro from hitting his pressure points, and the sight of his own blood makes him flip from from "effeminate man-glacier" to "rampaging murder machine." Due to his name, Mr. Heart has been quite popular for troll pics involving him replacing someone with a cutesy feel (Magical Girls, cute girls, or someone with a Heart in their name (like Arcana Heartino)) to make a high-caliber LOL Squick.
Rei, so, SO much. If a fan's favorite hero is not Kenshiro, it's Rei, with practically no exceptions.
Amiba, despite his relatively minor role in the overall scheme of things, he gets a bit of added exposure in the Gaiden spin-offs, particularly in the manga version of Raoh Gaiden, as well as in Toki Gaiden and Rei Gaiden. He even becomes Jagi's best buddy in the Dream Mode of Fist of the North Star: Ken's Rage
Juza is the only Goshasei to get his own spinoff so far.
Mamiya also has quite a fan following, if only for the fact that she's the only female character of the series actually able to do something useful. Added to that her being one of the most heroic females of the 80's animés.
Raoh, arguably the most popular villain, if not the most popular character, in the series. He is so popular that many fans consider HIM to be the series' true protagonist, and he is the only character to have gotten a manga, a Thirteen Episode Anime, and two movies centered on him.
Escapist Character: Kenshiro, seriously; who wouldn't wish they were a major Badass hero that gets to mow down villains by the hundreds while still being considered a borderline messiah.
Evil Is Cool: Raoh, Kaioh, Jagi, Shin, Mr. Heart, Ryuga and Souther
Fashion-Victim Villain: Most of the bad guys dress like Conan the Barbarian characters, only more colourful. See any grunt who has twin ponytails... on an otherwise bald head.
The villain Yuda is named after Judas Iscariot, the man who betrayed Jesus in the New Testament. Yuda's role is betraying the Six Stars of Nanto by siding with Raoh in a time of chaos, and all because he was jealous of Rei's elegance.
More recent adaptations only hammer the point home by romanizing his name as Juda (still pronounced "yuda" though).
First Installment Wins: More like "First TV Adaptation Wins". Many fans of Toei's adaptation considers Toei Animation's version to be superior than North Star Pictures' adaptation, where Toei's version was more emotionally driven.
The entirety of the Raoh Arc is the most well-known part of the Manga, while everything that comes afterward isn't regarded as highly. The Jako/Kaioh Arc was considered to be not as good as its predecessor, but still entertaining. The third arc, however, is criticized for being directionless until the Bolge chapters.
Fixer Sue: Kenshiro. By the post Shura arcs of the manga, he had become so incredibly powerful and predictably invincible that the only way Buronson and Hara could utilize him in a fresh manner is turning him into a passive observer who occasionally steps in to give a (heavy) helping hand and teach Anviliciousmoral lessons rather than to administer the asskicking that the audience had come to love him for. The authors could not even be bothered to throw one last big villain at him, having exhausted the villain coolness pool long ago with Raoh's (and to a lesser extent, Kaioh's) death, and instead gave him a villain who was more in line with the Faux-Elite Mooks Ken had routinely splattered all over the wall by this point. Toei Animation chose not to animate the post-Kaioh storyline for this reason.
Kenshiro bravely bears the sadness of the entire world on his broad shoulders alone so that nobody else ever has to cry again. As the big guy himself puts it:
I refuse to build my own future on the blood and tears of others!!
Rei. Nothing ever goes right for the man, and if you don't want to give him a hug in his final days then there's something wrong with you. Hands down, his death is almost unanimously considered the most tragic and tear-inducing in the entire series.
Due to not securing the FOTNS license for Western gamers, the Sega Genesis game was retooled into a new IP known as Last Battle. The characters were all renamed (Kenshiro became "Aarzak", for instance) and most of them recolored, along with the blood being removed, but by and large, the plot is largely the same. The Opening Scroll even spoils most of it!
The Sega Master System game had it even worse. It was retooled into a generic kung fu-based sidescroller known as Black Belt, but Mooks still explode when hit with an attack.
Kaioh kills his sister Sayaka just so he could frame Kenshiro for her death and drive Hyoh insane.
Jagi chaining a cinderblock to a child's leg and stranding him in the middle of the desert to both spite Kenshiro and amuse himself is something only a truly amoral, evil individual would do.
Ryuga trying to murder Toki, who was already on the verge of death from radiation sickness and after his fight with Raoh. And that's just the bowdlerised anime version. In the manga he also kills many of Toki's patients too for no reason.
There are quite a few people who find the series' casual brutality and plentiful bloodshed disturbing and sickening.
Nightmare Retardant: The over-the-top violence and gore can go from Nightmare Fuel to absolutely hilarious. In the manga, Kenshiro looks exactly like Mel Gibson in Mad Max 2: Road Warrior. In the anime, he resembles Bruce Lee (at least for the early episodes of the first series).
The Problem with Licensed Games: There has been a fair share of rather mediocre Hokuto no Ken video games throughout the years, most notably the very first Famicom game, a Kung-Fu Master-style side-scroller. Entering a door to proceed requires the player to press up and both buttons simultaneously, but anyone who doesn't know this will get stuck walking in an infinite loop on the very first level. It was also quite a difficult game, with knives and enemies flying into the screen all the time and no full life recovery between stages. Despite the fact that it was quite a rubbish game by any objective standard, it managed to sell quite a lot of copies in Japan due to its timing (it came out at the height of the manga's popularity and during the Famicom boom). More recent games, like the 2D fighting game by Arc System Works and Fist of the North Star: Ken's Rage are decent games in their own right. Even the 3D action game that was published by Bandai for the PS1 in 2000 was well made.
Of the various martial arts, Gento Kokken is the least popular, largely due to its Beam Spam nature conflicting with the normally semi-realistic feel of the franchise's other martial arts.
Seasonal Rot: The third and final part of the manga, which Toei did not animate.
It's not a coincidence the Hokuto no Ken 2 anime series was the only adaptation of the Shura/Kaioh stories, period. All other depictions have concluded their timelines with Raoh's death, though Kenshiro Den's opening goes slightly further and essentially serves as an epilogue.
Though various video games and Hokuto Musou 2have had stories both during and beyond Part 2 of the series, it's just that most of the major adaptations/spinoffs have ignored Part II and beyond except for Kenshiro, Toki, and Raoh's homeland being Asura/Shura.
Ken's Rage 2 is one of the few, if only, adaptations to go the whole distance and inclued the entire story including Bolge.
So Bad, It's Good: The tongue-in-cheek Manga Entertainment dub of the TV series definitely qualifies. It does have fans, some even considering Lex Lang's performance as Ken being one of the best roles of his career. Peter Lurie's performance as Jagi is also quite well done. There are some criticisms, such as Daran Norris' take on Rei. Its supporters consider it a shame that the dub was left unfinished.
The French dubbing is also (in)famous for being intentionally So Bad, It's Good, and being absolutely hilarious because of that.
So Cool It's Awesome: In spite of the aforementioned Seinfeld Is Unfunny, this is still a pretty fun Anime to watch/Manga to read 30 years after its release, and it's understandable why it influenced so many other Japanese works.
Squick: Not for the weak of stomach, this franchise is.
That One Boss: Despite his status as a relatively minor villain in the manga and anime, Alf is a notorious among players of the Mega Drive Hokuto no Ken as a sub-boss who can pin down Kenshiro with his ability to surround Ken from behind with a clone of himself.
Another source of dissonance for Western audiences can arise from Ken's forgiving of villians because of their Freudian Excuses, even if they're mass murderers (Souther, Ryuga), serial rapists (Yuda), or Social Darwinist tyrants (Raoh, Shin, Kaioh) who have killed many of Ken's True Companions (Raoh with Rei and Fudo, Souther with Shu, Ryuga with Toki, Kaioh with Schachi). In Japan, criminals who show remorse for their crimes are often treated less harshly, so Ken's forgiveness can seem less misguided if seen from that perspective.
Viewer Gender Confusion: Many Western fans erroneously think that the TV series' theme song "Ai o Torimodose!!" was sung by a male and female duo. In fact, it was two men. Also some Japanese fans mistakenly believe "Tough Boy" singer Tom to be male when she is female.
The Woobie: Yuria spends most of her time being kidnapped and dragged around the wasteland. And by the time Kenshiro catches up to her she's dying of radiation poisoning, although she does get a few years of happiness with him.