Kenzen Robo Daimidaler

Both have fetish as their main theme, and both have the same bad guys whom were much enjoyable than the protagonist. But KRD was more of ecchi while OTN was more about gender bender. 

These series are basically twins, just one deals with demons and stuff while the other is a mecha parody. Produced by the same studio, Daimidaler and DxD share the same artstyle, the same kind and amount of ecchi, even the main female MC is voiced by the same actress in both series. Both are fun to watch and provide lots of fanservice. Although Daimidaler isn't very popular, it's really worth checking out if you like the genres. 

Blue pill can be expensive sometimes, just grab a blue comedy anime as a stimulant. Will only cost you some brain cells, effects aren't 100% assured. 

Both have humans fighting against animal-like aliens (penguins in Kenzen Robo and insects in Dokyuu Hentai) trying to take "sex energy" from humans. Kenzen Robo uses mecha to fight the aliens, while Dokyuu Hentai uses super heroes. But the most importantly even if you dislike mecha/super heroes (like me), both anime have plenty of ecchi moments and female nudity for you to enjoy :) 

Similarities: Both have the same mecha, harem and ecchi genre. Both have the same guy character who is a delinquent. Dissimilarities: 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 

Both anime parody the usual serious mecha anime with carefree attitude and playing with tropes. 

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)  

The shows aren't that similar in plot or anything, but I think they both do a great job of parodying different anime tropes. 

Both anime treat about pervertcy and thier value in youth life (or smth like that) + dirty jokes. 

Its nothing like robotic;notes but i just wanted to recommend this underrated af parody of the mech anime genre and for this one the dub is somewhat more enjoyable. 

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. 

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  

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. 

Parody/homage to 70-80s anime. Enma-kun of Comedy/Ecchi, Daimidaler of Super Robot/Ecchi. Both are quite horny but more for comedy than fanservice's sake. Most importantly they don't take themselves seriously and that's why they make it all work. 

Main character-wise they are very similar; hot blooded and of course very perverted. Both Kouichi and Kakeru both find themselves surrounded by females Although there are no mechs in Akkikan! 

Both anime are highly philosophical and thought provoking, and also both have lots of penguins. 

the MC looks the same plus a few other traits but Kenzen Robo Daimidaler is Ecchi, Mazinkaiser SKL bloody 

Both shows are the "screw all logic" kind of show, both belong to the "so bad it's good" tier Turn of your brain and it will be a damn fun ride