My god...
I am almost salivating over this wonderful, picture-perfect film.
-The animation is astonishing.
-The music is orgasmic.
-The characters are tragic, even the demons.
-The story may seem simple, sure, but the music, animation & character personalities make up for any pacing/story shortcomings, which are slight inconveniences.
Nothing is perfect but for me, it lmost is and I love it.
My tiny critique is the pacing due to the flashbacks BUT honestly, they are necessary for emotional buildup. They teach and give insight into the characters.
Fights become more epic if you get attached to the characters, don't you know.
It would be tiring and less emotional/realistic without backstories. Relying on just the fights would not be as impactful.