I enjoyed this anime, but I think it is overrated
Overload of angst, incredibly convenient plot-twists... I mean, how often does the characters end up in the exact same small-town beachside... and then run into the same characters with overwhelming consistency?
Having been an anime-head for 2 decades, it's basically a check-box for the genetically-modified/robot girl genre.
Cute girls with amazing super powers, but are plagued by an incredibly sad history.
There is the usual round-up of supporting characters... well-intentioned but regretful father figure; cute nice guy which every other girl in the show seems to fall head over heels over; sweet girl who is constantly thwarted by her attempts to let the boy know how incredibly attracted she is to him, no matter how idiotically he behaves.
The girls use their powers to kill everything within a second, except if it's a major character, then they need 10 minutes to inflict a fatal blow.
As I said, I enjoyed it, but somehow, these formulaic animes are considered 'edgy' simply because of the excess blood and nudity, but if it had been done in Hollywood it would be considered exactly that... bland and formulaic.
I'm sure newcomers to anime would be enchanted by its lack of inhibition, but seen in the context of anime, it's just another uberpowered-kawaii-girl type cartoon.