It's quite a clever SF film with multiple layers of Philip K. Dickery. It's got romance. It's pleasant. (It's also CGI animated, but cel-shaded to look hand-drawn. It's reasonably well done, but we still have Bland CGI Faces.) Personally, though, I didn't quite buy the premise and so, for me, I don't think it quite worked. I still enjoyed it, but I didn't adore it and I felt no need to keep a copy afterwards.
My review will contain spoilers, incidentally.
It starts out in an ordinary school setting, albeit set in the year 2027 with cool-looking augmented reality. The realistic scenes are likable, but don't last very long. Soon we're into Dickery... but even saying that much is definitely a spoiler, so feel free to bail out now.
1. Katagaki Naomi is a timid loner who'd like to become capable, one day, of speaking up and being decisive. The world is full of things beyond his ability, e.g. getting a girlfriend. He'll deny wanting one.
2. Ichigyou Ruri is also a loner, but an almost aggressively direct one who says what she thinks but can't use modern technology.
3. Mysterious Bloke Who Appears From Mid Air And Has A Crow Sidekick...
It's a virtual reality story, but with an unusual justification. It's a recording of the past. The world's full of cameras, recording every action that anyone ever does. Put that data together and you'll have a virtual copy of the world.
My problem with that premise is that I don't see how these recordings could gain sentience and independent action. They think they're real... but they're just video clips, aren't they? It's as if your bookshelf became self-aware. What would it even mean for a recording to change its mind about what happened? I managed to go along with it thanks to the word "quantum" (which the film uses) and a thick layer of SF genre what-the-hell, but I still see it as basically incompatible with the concept of recordings.
Mysterious Bloke is from the future, but not really. It's not actually 2027. Katagaki only thinks it is, because he's a recording from 2027.
It's not that hard to make yourself swallow the premise, though. It's there in front of us. Just go with the flow. If it doesn't match the explanation we've been told... well, maybe that had been a simplification, or a lie. Maybe that's what happens when you put that all the information in the world into quantum computers? If you accept that, you'll get a film that can feel a bit mundane sometimes, in the gap between certain explanation stages, but has some cool next-level ideas and wild action scenes. It's not The Matrix, because it doesn't have guns, baddies or any real violence, but it does have a stage where the visuals go crazy.
The characters are fine. I liked them, although they're not really the film's focus. It's about its SF ideas. However the cast's tiny and there's always an emotional basis for what's happening.
This isn't a bad film. It's a likeable, watchable one that will fall apart if you poke it too hard. I didn't quite believe in it, but I didn't stop watching and I also expect to watch its three-episode spinoff anime, Another World. You could do a lot worse than this.