This show is carried by its near flawless character development, unlike any I've seen aside from Violet Evergarden, and A Lull in the Sea, you get to watch children grow as if they were your own friends. Watching them learn in a hostile environment, and overcome the restrictions given and expected by the entire world that they know. Defying all laws and growing up as if it were the modern present day, while fighting to keep those they hate the most, alive.
The first 19 episodes of Darling in the FranXX were great episodes, very memorable, the characters each having a distinct and relatable personality, and overall just being works of arts themselves. The episodes in question were of high quality compared to the rest, great story telling, great internal plots, overall just a watchable experience. While the art of the anime itself can be ignored due to high quality I feel it rather fits in some parts, with the simplicity of the characters designs contrasting with the backdrops and scenery you can feel the difference and feel as if they don't fit where they've been placed in society.
SPOILER AHEAD:
My personal favourite episode, is Episode 13, which I found to be one of the most heart wrenching episodes in anime that I have watched up to the point of me writing this, the sheer horror, guilt, hatred, and realization you feel while watching how the two were treated, experimented on, and confined, gets you feeling a great hatred for those who oppose them, and a great sorrow and empty feeling for Hiro and Zero Two.
However, as I stated before, the episodes from the beginning to episode 19 were high in quality and production value compared to the later section. While I beg to differ that the very end of Darling in the FranXX was terrible, one thing I can agree on was the episodes building up to the finale weren't, as you could say, horrible, but more like just completely unrelated to the rest of the series and steers from the plot entirely, as if they just gave up and decided to change the genre, theme, moral, and even the characters personalities.
Episodes 20-23 felt like a rush to use up their budget, introducing a new concept, VIRM, to the mix could've been executed a lot better but you can see where they could take it from there and handle it well, but they definitely didn't. The following episodes was a whole lot of 'What in the fuck is happening?! Someone has got to remind me that ZeroTwo is a woman, Ichigo is a bitch, and the fat dude who we forget the name of was absolutely betrayed!'. In Short, those episodes strayed so far from the initial plot build that as it moves from the plot you move with it and you totally forget the point of everything, it felt as if 2 seasons worth of content passed in less than two hours. 90% of the stuff within the episodes has to AT LEAST be explained.
The very final episode in the last few minutes was pretty good however, the first half of the episode was more of a 'This happened 20 years in the future by the way', which I felt could've been executed better in some way, but the last few minutes of the episode, with Zero Two and Hiro, having prior sacrificed themselves for the protection of their people, eventually returning to earth and reincarnating as a young boy, and girl, to cross paths together and join once more. Which I found to be just a beautiful way to end the series.
Overall the plot and character development was pretty good at the beginning, but the end ruined it and threw away all potential they had created for themselves, and I just do not understand anything.