Just watched it
Here are my thoughts,
It felt very american. I guess because the author wrote the screenplay. Except for the characters speaking japanese, there was very little to really distinguish it as a japanese film.
I liked Maki as Naomi. She's a little too cutesy at times though. The only other thing I've seen her in is Hana Kimi, and she was pretty much exactly the same here. After she cut her hair, I had a hard time distinguishing Naomi from Mizuki.
I liked Kenichi a lot, he's very good as hot, mysterious guy so I was a bit sad he went crazy and she ended up with the other guy
This was the first time I've seen Yuya in anything I think. I liked him as well. Still hoped he'd be the unlucky childhood friend though. However, I did like the reveal that lead to him being a potential love interest. Naomi was a bit mean not telling him in private that she got her memory back. Mirai deserved a happy ending though
I was surprised to see that Anton's character wasn't a complete *beep* as I expected going into the film. I really like Anton Yelchin, but he felt a little out of place here. I think he overacted a bit.
I loved all the japanese-accented english.
I liked the way they showed the photos popping up all over the place.
The final voice-overs were a bit much though.
All in all, I liked it a lot. I don't think I've seen a decent new teen film in a while so it was refreshing.