The 47th episode, "Revenge of the Juralians", happened far earlier chronologically.It makes sense. The events being chronologically early is perhaps the only way to handwave the fact that Maou did not see Chargeman Ken as a threat, despite Ken being extremely effective at slaughtering Jural Seijin and the episode being the 47th. Plus, the speech that Maou gave (which also implies that the original Jural homeworld was destroyed) contributes to this.
Maou-sama holds a harem.And just about every female Jural shown in the series is part of it. After all, Maou-sama is a dictatorial king with absolute power.
Dr. Volga never had a bomb in his skull.Ken just heard the clock ticking and misinterpreted it for Dr. Volga being a Jural robot with a bomb in his skull. In fact, Dr. Volga survived the gun shot, and Ken, thinking he died, thought he was a robot. Because of this, Ken killed him - by dropping him on the Jural spacecraft. It exploded not because Dr. Volga had a bomb in his head, it was because Jural rockets are so horrendous that they can explode if a human body is dropped on their saucer. Hell, even Maou's gigantic saucer suffers from this!
The Jurals are a far less physical race than humans.Which is the reason why they are Immune to Bullets yet die from one laser beam shot, the reason why they seem to be so incredibly good at disguising themselves as humans, the reason why they melt when they die.note
The Jurals are agender.In fact, they are pretty much either asexual or hermaphroditic. Some Jurals do use feminine or masculine pronouns and refer to themselves as female or male, but biological gender does not exist in their society. The only biologically gendered/sexed (in this case, masculine/male) Jural is Maou, although that might be because he's half-human, as stated in the theory below.
General Maou is a Jural-human hybrid.Compare a Jural◊ and General Maou◊. The red sphere on General Maou's forehead is his third eye, derived from his Jural parent. Considering that Jurals can disguise themselves as humans, there is quite a bit of evidence for Maou's human origin.
Not only that, Jurals and Humans once lived together on Earth.Not only can Jurals disguise themselves as humans, they are good enough at it that a guy marries an undercover Jural and doesn't notice. Another episode, there is an undercover Jural going by J-7 who meets with his superior after he flunked a mission. When the superior says that Earth is just the enemy and should not be sympathized with, J-7 replies with a speech that ends with: "Earthlings protect each other. They may even cry over beautiful things. And just like us Jurals, they return once again to what they have lost!"note
Long story short, the Jurals and Humans once lived on Earth together, but for whatever reason the Jurals left for another planet. By the time they came back to Earth, the species had evolved so differently that they were hardly recognisable to another, and Fantastic Racism kicked in.
- I like this theory. Hell, a translation of one episode has Maou say: "We will finally bring peace and prosperity to the Juralien race!". It makes him a Well-Intentioned Extremist. An abusive, genocidal, sociopathic Well-Intentioned Extremist who has no regard for human life, but then again, Ken is not exactly an angel either.
The year Chargeman Ken takes place in is 2X77.The translation of this episode has a scene in which Maou kidnaps Ken's parents. Ken's dad sees a guillotine, and, as he says, it is "something we humans used hundreds of years ago". The last time a guillotine was used was in 1977, in France, until the abolition of capital punishment.
Volga being dropped on the Jural ship was what he wanted.Volga, whether he wanted to be or not, was a bomb. As much as Ken does questionable things, Volga would have blown up Ken if he wasn't ejected from the ship, and there didn't seem to be as much "heroes" to fight the Jurals as there needed to be. Perhaps Volga knew this, and was content with his fate.