Art style can only be described as a 1980s twist on 1960s character designs. The weirdest blend of cartoony stylized & realistic anatomically correct characters co-existing like it's Cool World. Kakugo's head looks like realistic fanart of Nny from JTHM.
Comes off as unintentionally funny because I think the series is taking itself seriously while being so bombastic.
The main villain, the naked chick, is actually Kakugo's older brother (not a spoiler, it's revealed early). Still uses male pronouns after the sex change to female, which happened to his body after merging with the Kasumi armor.
Feels like an homage to Go Nagai & 80s horror animes. Makes me think of Devilman or Baoh fighting Onepunch Man monsters. Has Crying Freeman levels of gratuitous male nudity used in combat.
There's a minor art shift for lesser characters that causes Haoka to look like a teenaged Zenigata from Lupin III (boosted by the fact that their teacher is naned Zenigata).
The monsters are basically horror versions of the creepy senior citizens in Studio Ghibli films, like Yubaba from Spirited Away, & The Witch of the Waste from Howl's Moving Castle.
So it's 50-50 on male to female nudity. The nudity is almost never sexual & treats nude characters as if they were fully clothed & going about their daily lives, or even like the lack of clothing is an advanced form of combat armor. When it is sexual, it's associated with revolting grotesque monsters in bondage outfits you'll wish were clothed. The female nudity is almost tasteful, with very small unexagerated realistic body proportions you won't find in hentai or ecchi. The male nudity is hyper detailed but censors the genetalia.
On the Devilman thing, Harara is like a blend of Sirene & Ryo & Kakugo is like a stoic Amon.
The hero's love interest Horie is not exactly stock standard for a shounen series. She's on the doughy side with a body not unlike a Chibi. She develops an instant crush on Kakugo, but he shows no interest in her, & is eventually won over by her strong personality, caring nature, & defiant spirit.