There once existed a planet named Beal, until it was wiped out by the mysterious entity known as Gaizok. The few remaining survivors escaped to Earth and split into three families, named Jin, Kamie, and Kamikita respectively. While attempting to start a new life, the collectively known "Jin Family" prepared for the inevitable Gaizok invasion on Earth and its giant mechanical beasts known as "Mecha Boosts". In order to defend their new home, they have built three vehicles which when combined form the mighty Zambot 3. The Jin Family must not only defend against Gaizok attacks, but also harsh criticisms from the very people they protect, who blame the Jin Family for the invasion in the first place.
It's very rare to watch an animated series and be genuinely horrified or shocked by what you're seeing. The other shows I can think of that really achieved this were Legend of the Galactic Heroes, FLAG and Dougram, but that's more because they starkly depict war crimes and political corruption that can hit very close to home in the current political climate.
Zanbot is very different. It sets itself up with a perky theme tune and plucky kids as the main characters and you expect a traditional super robot show.
Then it doesn't come. What you get is something hard to watch at times simply because it
takes a look at what happens if a genuinely evil force, one who don't care about anything except winning, try their hand at attacking Earth. There's not so much "wait for them to form their robot so it's a fair fight," or "send one enemy with an obvious weakness" in this show. At 23 episodes the pace is breakneck, going from the first unsteady steps of Kappei and his friends at the controls to a series of ever-more sickening atrocities on the part of the enemies through to a deadly confrontation in space and one final, shocking twist.
The main villain for most of the show is Killer the Butcher, a grossly fat and decadent alien who is essentially the archetype on which all psychotic villains in mecha shows try to live up to. And to be honest, with the exception of perhaps Gates from Full Metal Panic: The Second Raid, none come close. While humanity is fighting for its life, he's shown singing karaoke, playing pool, smoking what looks like an opium pipe and grotesquely eating vast amounts.
He abuses his generals, toys with his prisoners and is unafraid to use terrorism instead of a super robot to fight humans. His mission is the genocide of the human race - not conquest, only murder.
So from this alone, you can see how the show is very different from an average show ala Mazinger or Voltes. There's a telling quote from the show's most unpleasant arc, the human bomb arc, where he says suicide bomb attacks are more effective than any kind of robot.
The death toll is shocking, not letting up even in the final episode. And unlike Victory Gundam's absurd impalements, explosions and death by wheel, Zanbot's main character deaths are quite chilling and effective.
As if the show couldn't be any bleaker, there's another plotline that's particularly interesting. Humanity is shown to resent the idea of super robots, and placing all their hope in one team who they never knew very well, and understood only to be untrustworthy and eccentric foreigners. Simple racism and paranoia is as powerful an enemy in some episodes as the alien invaders, and that's quite interesting.
The animation is quite dated, and the sound design isn't half as innovative or appealing as later shows. But it's worth putting up with this to watch a show that challenges the super robot genre in a most effective way.
There are also some wonderful visual cues in it that fans of Tomino's other works will recognise as being used in later shows - much like Nadia had a ton of stuff that would turn up in later Gainax shows, Zanbot brings to the table an early version of the Ideon Gun (Space Runaway Ideon would air in 1980, almost three years after Zanbot) and a particularly climactic scene which would be reused in Victory Gundam almost exactly.
A little background on how i found this old school gem, there was a magazine that talked about all of Tomino's work before gundam, this was one of those anime's. I was reminded of this little article by watching Gurren Lagann (GL takes some themes and mecha designs from this) So after some searching i finally found this. And was it worth it. The story starts out as your basic monster of the week sort of super robot anime, but each episode explores how these fights effect the population and how they react to the pilots themselves, the show gets more intense with each episode
with what i would call a perfect ending. For its time the animation is very good too. So if your looking for a great old school anime that really isn't well known, give this show a try.