This is the film that Ghost in the Shell could have been.
Alita is a cyborg - specifically, a broken cyborg, found in the junkyard around Iron City, where so many of the remains of a recent war are left abandoned. Luckily, she's found by Dr. Dyson Ido, someone who makes something of a hobby out of repairing broken cyborgs, to supplement his hobby of stalking the streets mysteriously at night.
The stalking may or may not have something to do with a collection of cyborgs constantly going missing, and an army of "Hunter Warriors" (cyborgs for hire) who are trying to find out what's going on.
Behind all of this, the poverty and deprivation of Iron City continues, made all the more depressing by the existence of Zalem, the floating city above it. Zalem is the land of the rich and powerful, and no one is allowed to rise from Iron City to it. Which is a problem for Hugo, Alita's love interest, who is really very desperate to get up there.
That all sets up a "fighting your way out of poverty" storyline, with Alita hoping to become a Champion at the local sport, Motorball, a rather brutal affair. It involves various roboticised people driving around an arena on powered Heelys, while attempting to either do something with a spiky death ball, or murder everybody else in the arena. As you might imagine, being almost entirely robot, Alita is good at it.
Add to that various other plots about local crime, an evil overlord, the missing memories of Alita and a grumpy ex-wife, and there's enough to be going on with.
My favourite part of this, perhaps unfairly, is Christoph Waltz as robo-dad. His relationship with Alita is always surprisingly touching, and his worried paternalism is well played.
I've definitely got to flag up the CGI, because even though it occasionally flags in the most detail-heavy action scenes, the effects used to turn Rosa Salazar into an manga-esque character, with overly large eyes and rounded face is impressive. It takes a little while to bed in, but once it does, you won't notice any weirdness.
Salazar gives a good performance, though is perhaps written somewhat too human for my liking. Part of the joy of the film is the number of ways the human body has been changed and adapted to cope for the dangerous future, and how far from human normal some of the character designs are. To then put into that Alita as the nearest version to human, but most powerful feels somewhat shallow. I know, I know, it's taken from the manga, but it was a shame to see less advantage taken of the rebuilt world.
(Though saying that, there is a very good fight scene partway through that pulls no punches on the effect of a robot body.)
It's also prepared to take a few chances with some of the character actions, and have some unpleasant consequences I wouldn't have predicted. Always nice to see a film not afraid to take things to a logical conclusion.
And most importantly, it features robot dogs, so it's obviously best film all year.