Short early review...
The animation feels dated, the story seems to be a bit all over the place, but it's not all negative.
The movie opens up with an intriguing start, which I thought would promise more of an interesting plot, though it's not that special.
I don't know what to really say without going into spoiler territory, but I do honestly think that it would be worth the watch as long as it's free. I myself paid 1900 yen to watch this and all I can say is that it was alright.
If you are very interested in parallel universes and paradigm shifts (which I am interested in myself, but this just didn't seem to work) I think it might be a hit for you.
But for me it felt slightly shallow, and I honestly don't know what else to say about it.
My apologies, I have now watched the first part of this movie, aka 'Kimi wo Aishita Hitori no Boku e' and my point still stands with this movie, it wasn't, in my opinion, needed.
Though I recommend watching it if you want the full experience from the 'first' movie.
Animation 5/10
Story 6/10
Sound 5/10
VA 5/10
Reminder, I am not fluent in Japanese, and I watched this in Japan, but I did follow the plot at an okay level, but it honestly didn't strike a chord with me.