I loved this film ! It excels at what it goes for, that being a romantic story between a girl and a boy mixed with some fantasy. My only complaints are mainly subjective but I'll still bring them up (spoilers) :
I think the ending went on for a bit too long, it could have gotten to the point faster and maybe spent more time on the aftermath.
I think the way Hinode finds out about the cat/human transformation is a bit underwhelming, the girl turning into a cat is the main plot point and you're waiting to see the payoff but it's not anything special.
Their love is a bit "random"
Now it's totally normal to have crushes at their age, I'm mostly talking about the ending when Hinode confesses his love for Miyo. I assume he has always loved her someway somewhere, but they don't ever hint to it until the end so it mostly comes out of nowhere.
Now what i loved the most !
The character's personalities and attention to growth
At first Miyo seems pretty basic, but throughout the film you learn about her and her struggles, she acts very childish but she's quite mature, she is super lovable especially as a cat ! I love the scene when she snaps at her family, you can really feel for her and it's really sad. Same goes for the other characters.
The emotional moments.