I hate long reviews so i ll make this quick and spoiler free.
The movie is an absolute masterpiece that will make you dying for the second season to air. Made in Abyss the only anime that can make this kind of mixture of cuteness and and darkness and wrap it all up in the most outstanding art and music creating a dream-like atmosphere that will make you live every second of it and end it with the bitterness of waking up from a beautiful engaging dream.
This is my first review btw and i was to submit it but the website asked me to make it longer for some reason.