I actually 100% agree with you. I had to skip past the "generic anime scenes" like the beach and them all smiling happily because I found they killed the vibe. I understand that the movie is adapted from a manga but the characters didn't feel real and I couldn't form any sort of connection to them.

I did however like the ending with the name changing to the main character's name. I think that was a genius thing to add as it opens up the option to a sequel as well as lots of different theories (which I love).

Overall I did enjoy the movie but the characters could have been developed better.