Continuing my watch of the 90s Kamen Rider films is 1993's Kamen Rider ZO.
For reasons I need not speculate on, Toei decided not to continue with the Shin Kamen Rider project. The following films would be fully unconnected to any larger story. Notably, both were directed by Keita Amemiya, who had previously worked on Lady Battle Cop, directed Zeiram, and would afterwards direct Hakaider.

Kamen Rider ZO is basically Terminator 2 but in a third of the run time, produced with a fraction of the budget, and with a guy in a suit instead of Arnold. It rules.
Loving father/evil scientist Dr. Mochizuki is researching the creation of a perfect life form, unbounded by morality. After later deciding against pointless creating evil monsters, he's imprisoned by Doras, an as yet incomplete monster aggrieved at being discarded.
Doras attempts to kidnap the doctor's young son, Hiroshi, as leverage to force the doctor to finish building it. Trapped within a Giger-techno-flesh prison, the doctor issues a telepathic plea to an earlier experiment of his which had escaped — the once human Kamen Rider ZO — to protect Hiroshi.

Not understanding the situation, Hiroshi believes himself to be under attack by two separate monsters. He's pained by his father's absence and harbors resentment towards him, even as he comes to realize that the unfamiliar man who knows his dad isn't a bad guy.
The film's suit game is on point, and most of the action is quite good, including a few commendable fights between the suit actor and a stop motion creature. There is goop and there is vinyl and it's all pleasantly gross. Kamen Rider ZO himself is a little generic, but Doras kicks ass in all of it's myriad forms.

It's also lowkey horny for the male body in a manner I wasn't expecting. There's more than a little shirtless male bondage, and ZO befriending the son of the man who experimented on him kinda has some "awkwardly introducing yourself as dad's gay partner" vibes, even if that's not exactly what's going on.

Less positively, there's some rough edges. We spend a lot of time being introduced to the Hiroshi's family and friends, including his eccentric inventor grandpa and some teenage karateka, but they mostly don't matter. That isn't necessarily a problem, but its weird we get that instead of more insight into Dr. Mochizuki. It's a weakness that we're not shown why he decided to create a race of evil monsters to replace humanity or when and why he changed his mind. The doctor also seems to have some weird connection to nature? He has grasshopper telepathy from the previous film.
While Shin ('92) was 45 minutes of story painfully stretched to twice that length, ZO occasionally feels like a longer story compressed into 45 minutes of film. However, in this case that was to its benefit. ZO is a very entertaining watch, and probably my favorite of the three films.
