It is dangerously easy for grimdark stories to get excessively grim. This can go wrong in a number of ways. Sometimes the audience is just so crushed that the angst dulls their appreciation of the story; more often, the angst is too amateurish, and it turns into Wangst.
Sometimes, even if the writer(s) can avoid Wangst and Anvilicious Sledgehammer Angst, the story can get hung up on unpersuasive stylistic tics.
If the audience is constantly snapped back into criticism mode, immersion is not possible.
(E.g.: Dr. Adder is a story all about sexual tics that would have been shocking in 1962; it was shocking when it was written, circa 1970, but it was already badly out of date by the time it finally found a publisher brave enough to print it – in 1984. One can still read it – it’s not a bad style piece – but it’s like critiquing a student project – everything feels artificial and hollow. The constant writing about sex seems to be the author venting his own neuroses rather than telling a story.)
By contrast, Battle Angel Alita is a dark, brooding cyberpunk noir story that isn’t afraid to use shopworn stereotypes, starting with the amnesiac heroine, which has got to be one of the most over-used stereotypes in modern history. Nonetheless, the story works. It’s a workmanlike little piece. The two-episode OVA introduces a serviceable Action Girl heroine. It’s very believable that she’s a super-warrior, because she’s not a woman, except for her brain, her blood, and perhaps a few auxiliary organs. She’s mostly a hyper-advanced combat cyborg, so her body is just super-strong and super-fast, with excellent combat instincts.
This is a show that introduces us to a likeable warrior character – technically female, but I get the feeling that the author understands fight scenes and doesn’t really understand mushy emotional stuff. The heroine isn’t really a sexual being – she has a good heart, and mushy feelings of loyalty and friendship, but she’s a childish symbol of adventure, not a realistic character with convincingly-depicted sexual needs.
I’m not about to go and seek out the manga – the OVA wasn’t that fascinating – but it’s a decent little story. I can guess that the manga goes on for volume after volume of repetitious comic-book style fist-fights between super-powered cyborgs.