This terrific fantasy focuses on a girl who discovers she can jump back in time, and much of the movie is a light-hearted exploration of what a teenage girl would do with that power, which is essentially relive life better, avoid uncomfortable conversations, and eat pudding. The lead character is likably average.
There are a few oddities in this movie. Some of them are because it turns out, as I learned at wikipedia, that this isn't actually the same story as the novel upon which it is based but a sequel containing a character from the original movie, which explains a lot. Apparently the original story has been made into several movies and TV series in Japan, so the assumption was probably that everyone would understand a lot of references I didn't get.
Also, towards the end, we are given little pieces of information that suggest there is a whole other story to learn, although whether that story is in the original book or whether that would be the subject of yet another narrative I don't know.
Then there's the ending, which is logically unsatisfying and yet which I ultimately found emotionally resonant. It's one of these puzzling endings that has you reading wikipedia and going through the IMDb forum posts (which offer a lot of fascinating theories).
Well worth watching.