In my opinion:
Both where based on a very simple premise, that would make one's head scratch. Both also has the same MC who rather have some very obnoxious fetish and it also includes some harem romance, sci-fi and ecchi genre. Also, both animes have antagonists who were seemly a bunch of nice guys. But, the focus of each anime diffres since one anime was all about that "Hi-ERO" thingy, while in the other anime is more into that twin tails thing.
Just go and watch it and do scratch your heads if you do feel like scratching it i you seemly can't dig those two animes.  read more
What the two have in common:
Both have the same theme based on a very simplistic random fetish plot.
Both also have the same over the top monologue, that is just a bit too much for something so simple.
Both have the same kind of antagonist versus protagonist kind of thing where the antagonist where more lovable than the protagonist.
They both have the same plot where fetish was the main theme, but, one was more about gender bender while the other was more about the female MC who has the unlucky role of having to endure the male MC's sexual advances.
Imagine Highschool DXD turned into a Mecha series. Same character designs and action!! Main character gets his powers from oppai and other perverted things. Kouchi=Issei and Kyouko=Rias. Coincidentally Rias and Kyouko have the same voice actress too.
Main character is a pervert. He gains the ultimate power by being one. Both main characters meet the girl of their dreams who help him out. The source of their power up. One series involves demons while the other is a mecha series.
Both have the same mecha, harem and ecchi genre.
Both have the same guy character who is a delinquent.
One the main guy in one anime is still a virgin, while the main guy from another anime is..................I don't know, maybe he has gotten laid.
The main girl character in one anime has to serve as the guy's play thing......to increase his "Hi ERO" powers, while in the other anime the girl co pilot serves as the guy's.............I guess we'll find out.
The antagonist in one anime where.....let's just say on the horny side, while the antagonist from the other anime where basically on heat.
Daimidaler has all the makings of a typical Go Nagai anime adaptation. It shares the same hot blooded main character, Endoh opening and an enthusiastic narrator, and of course, giant robots. To further illustrate my point, even the 3 professors in Daimidaler are a direct reference to the 3 professors in Shin Mazinger, namely Sewashi (Sewashiko in Daimidaler, ko to denote that they're female), Mori Mori (Moriko) and Nossori (Soriko). The action is also very fun to watch. Daimidaler gives a great sense of weight like Mazinger Z. And should I note that the character design for Kouichi resembles Mazinger's Kouji with thick sideburns?
While Shin Mazinger doesn't have as many perverted scenes as Daimidaler, the show is exactly like another Go Nagai giant robot adaptation, known as Koutetsushin Jeeg with its overly lecherous MC.
If you enjoy Daimidaler for all the reasons I listed above (hot blooded MC, giant robots, great action, music), then you will surely enjoy Shin Mazinger and other Go Nagai anime adaptations. read more
Kenzen Robo Daimidaler is simaler to many of Go Naigai's works, it combines super robot anime, with his form of ecchi, which is somtething that Nagai never usualy does together
It is funny, gut busting, Super Robot action, with villains as crazy and wierd like you see in the classic Super Robot series, such as Mazinger Z.
When the world is in danger, the government created a giant robot/mecha as new weapon in order to maintaining security & stability using new source energy as main power.
- ERO-Particle as Daimidaler main power
- Orga Stone as Zetsurinou main power
However, to activating this new power, MC must perform some erotic/hentai scene inside the cockpit to achieve some level where MC can release his/her true strength. Even this condition done by duo couple not alone.
- Kyouko x Madanbashi (Kenze Robo Daimidaler)
- Nozomi x Unnamed-Male-MC (Inyoku Tokkyuu Zetsurinou)
Both MC's get dragged into fighting not knowing about there hidden potential and power
Both stories have multiple character relations through out the narrative
Both MC's get stronger after every battle
The two series have Comedy, Ecchi, and Action elements
Protagonists in both animes needs to recharge power of their robotic armors (giant mechas in Kenzen Robo Daimidaler) in a sensual manner.
Furthermore, both have Comedy as one of their particular genres.
Cheesy perverted characters, even crazier antagonists and enemies.
Both can be creepy at times with the antics of the characters.
One has mecha the other doesnt.
Both are ridiculous, full of ecchi and some hit and miss comedy.
Both anime are funny. Moreover, they both have giants battling other giants, but the main different between the two is that, while one is mecha, the other is just an alien making some girls bigger to protect the town.