It's a live-action film based on a highly successful 2012-16 manga, which also got an anime series and a Netflix live-action TV drama. (I've seen the anime, but not the TV drama.)
It's pretty good. I'd recommend it.
It stars the gerbil-faced Tatsuya Fujiwara (Death Note, Battle Royale) as Satoru Fujinuma, a loser with time-travel superpowers he can't control. He calls it "Revival". This activates when something bad's happening, sending him a minute or so in time and/or giving him a warning to try to change the future. This is nifty, but Satoru has no confidence, no girlfriend and no social skills. In conversation, he imitates a brick wall. In hindsight, this might conceivably be related to the fact that a serial killer was murdering children in his home town eighteen years ago when he was an 11-year-old in Hokkaido.
He's a pizza delivery driver. He's nobody important... until, one day, bad things happen and we learn that he's a total idiot. Lesson #1: if someone's been stabbed, phone for an ambulance and DON'T MOVE THE BODY. Don't pick her up and don't hug her. Lesson #2: when the police arrive, greet them immediately and explain the situation. Don't run away from them as if you're the murderer.
...and then he time-jumps back to Hokkaido. He's 11 years old again.
The acting's good. There have been films where I thought Fujiwara was miscast, but this is absolutely in his ballpark. No complaints at all. Kasumi Arimura is adorable as Airi, the adults are all solid and (most importantly) the children are superb. There's one reaction shot where I thought Tsubasa Nakagawa was very slightly lacking as young Satoru, but otherwise I forgot that I was watching child actors. That's how reliable they are. They're good, dependable actors who happen to be children. They get strong material to play, e.g. Hinazuki's abuse by her parents, and they don't drop it. Rio Suzuki has some strong moments as Hinazuki and I'm not at all surprised to learn that she's still acting today. She'll have a long future in the business and I expect her career to be worth following.
It's strong material. Child abuse, child murder... this is powerful and sometimes chilling. At the same time, though, the film made me laugh sometimes. Satoru's mum is the greatest. The film changes the ending, but apparently so did the anime. If you asked me which ending I preferred, I'd choose the anime's... but the film's version works too and fits better with the Japanese title.
To be honest, I prefer the anime. It has more screen time, more build-up and more atmosphere. If I ever rewatch this story, that's the version I'll probably go for. I do like this film, though, and I'm glad I watched it. I'd happily recommend it to people. It's a very good adaptation of a strong story and you can watch it in a couple of hours, as opposed to twelve episodes. It doesn't feel compressed, which is often a problem with live-action adaptations of manga/anime. No significant complaints with it at all.