Adaptation Displacement: Zig-zagged in a rather odd example. In Hawaii, people are more familiar with the 70's show than the original manga and the anime, while in the rest of the USA most people are gonna be more familiar with the anime than the 70's show.
Animation Age Ghetto: The anime seems unsure of who their target audience is, and it sort of scares away most people. The dark premise, violence, and sexual implications keep it away from kids, the very cartoony style, "wacky" characters, and bright colored animal robots seem too childish for more adult people to get into.
Awesome Music: The anime has a number of cool songs that fans have really enjoyed.
Theme of the Gemini which most feel is perfect for the more sombre tone of the series. Listen here.
The battle theme friends or enemies when Jero is forced into combat. Listen here.
The appropriately named Devil's Flute that plays when Gill is playing his flute to try to control Kikaider. Listen here.
Kikaider 01: Big Shadow is the leader of SHADOW, a criminal organization which seeks to exterminate one-tenth of Japan's population. To this end, Big Shadow kidnaps Akira and Hiroshi for the Giant Devil blueprints tattooed on them and orders both children executed once he's copied the plans. When the Giant Devil nears completion, Big Shadow tests out its power by having it carpet bomb a city. He also pursues other ways to kill lots of people, including attempting to drop an atom bomb on Tokyo and distributing pens to schoolchildren that explode upon being used. He later creates Mari/Bijinder to use her to gain Ichiro's trust so he can blow them both up with a miniature bomb implanted in her chest. When Mari defies the plan, Big Shadow has his henchmen beat her and later orders her lobotomized by removing the conscience circuit Ichiro installed inside her. Hiring the assassin Waruder to deal with 01, Big Shadow has Hakaider murder every dog within radius of SHADOW's base so Waruder will not be distracted by their presence. In the final episode, Big Shadow abducts Dr. Komyoji to force him to create a robot-repairing machine for SHADOW and attempts to have him executed by guillotine once the machine is completed.
Android Kikaider: The Animation: Saburo/Hakaider, lacking any of the redeeming qualities of his original counterpart, is instead concerned solely with fighting his "brother" Kikaider and having fun while doing so. Created by Dr. Komyoji and repurposed by Professor Gill, Saburo's introduction sees him murdering a fellow android who showed mercy to Jiro and Mitsuko. He later takes control of Jiro and forces him to commit a series of obscene acts to break him so he'll show his true power, starting with stopping Jiro from saving Mitsuko's mother from committing suicide. Saburo then forces Jiro go on a rampage through the city, killing a police officer in the process. When all that doesn't work, Saburo makes Jiro strangle Mitsuko. When Jiro defeats Saburo but refuses to kill him, Saburo attempts to shoot Dr. Komyoji's brain out of spite.
Hakaider, big time. So much so that he was bumped up to being the Big Bad of the sequel series, given a squad with three more versions of him and later even got a movie based on him, which only amplified the popularity.
Fridge Brilliance: When Jiro sheds a tear late in the show, Gill looks terrified as he considers how Jiro's Gemini Circuit could be changing. While it took Gil's submission circuit in the OVA to finish the job, he likely realized that if Jiro developed enough, he would be beyond any means of human control. While Inazuman would get Jiro back to his senses, Jiro is still under his own control.
Hawaiians Love Kikaida - The live-action version is one of the few tokusatsu programs that has actually gotten a legitimate DVD release with English subtitles, although it's only available in Hawaii.
Anime Saburo crosses it when he starts forcing Jiro to go on rampages, even attempting to make him strangle Mitsuko at one point, all in order to get him to unleash his full power.
While he guilty of plenty beforehand, Professor Gill really steps over the line in the OVA when he uses Akira, his own son, to power his Giant Devil robot without caring about any harm that might come to him from it.
Narm: The anime has a few, especially in the English dub.
"Is that a good order... or a bad order?... Either way, I'm not taking any orders, because I'm just a mad machine." — Jiro, after Mitsuko tries to order him to come with her after the second Monster of the Week's attack.
Also, when Jiro yells just a MACHIIIIIIINE!!!
One-Scene Wonder: Considering the OVA only has four episodes, and Rei/00 is introduced in the third episode, we don't really get a lot of time to actually know much about him at all. Another example would be the golden bat vampire robot, who is amazing.
The Scrappy: Ichiro/01's anime incarnation, who's bratty, annoying and even sounds a bit like Scrappy. His counterpart in the live action show on the other hand is a lot more well-liked.
Special Effects Failure: In the OVA it's pretty obvious in one episode that instead of animating the androids and objects falling, they simply moved a still image of them across the screen to appear as if it's animated.
Somewhat justified for the live action shows' monsters, as they are supposed to be robots...
Uncanny Valley: Kikaider's large, emotionless yellow eyes. A brief shot at the end of the OVA even has an un-transformed Jiro sporting them. And then the Code 02 Manga ups the ante by giving him a Glasgow Grin and decidedly skull-like head.
They Wasted a Perfectly Good Character: Hakaider Squad's appearance in the Kikaider 01 OVA mostly amounts to showing up in the second episode, transforming into Gattaider, fighting Kikaider and 01 and getting destroyed, leaving little consequence on the plot. The fact that they're destroyed the episode before Rei/Kikaider 00 was introduced, it feels like a huge missed opportunity to have a four-on-four fight between the Kikaiders (plus Bijinder) and the Hakaider Squad.
What Do You Mean, It's for Kids?: The 1970's toku, much like the Kamen Rider shows from the same period, often features the various monsters of the week killing civilians in gruesome ways, though it can be either scary or silly, depending how much you mind the dated special effects.
What Do You Mean, It's Not for Kids?: The manga and anime adaptation in spades. Don't let the colorful robots and silly characters fool you, there is a lot of murder, blood, and suicide in this series. This is Inverted in Japan, however, where it is in fact aimed for kids, and actually aired on the Japanese television channel, Kids Station.
Complete Monster: Gurjev is the angelic dictator of Jesus Town, ruling it as a totalitarian state. A firm believer in The Evils of Free Will, Gurjev orders his State Sec to capture any dissenters for him to lobotomize—even innocent children—removing all of their emotions and willpower. Revealed to have been Hakaider's original creator, Gurjev saw the android as a "failure" and abandoned him, replacing him with an obedient and loyal weapon. After successfully massacring La Résistance, Gurjev tries to kill Hakaider even after the latter had spared his life.
Fanon Discontinuity: Quite a few fans disregard this film as they see the implication that Michael really is a brainwashed Kikaider as a defilement of their childhood hero.