The animation is nice and the parkour scenes, while not instructive or realistic in any way, are fluid and nicely done. However the characters and the plot are so derivative!! And not of The Little Mermaid, which a character has to read and then incessantly quote from, just in case we're really dumb and don't get it, but of every Japanese anime ever. Lovely innocent child-like magical girl? Check. Kind, shy, weird and skillful boy? Check. Group of diverse (in the Japanese way) nakamas that will help the hero reach the goal? Check. Magical unexplained phenomena that people treat by leaving and eventually using it as a parkour course where no one seems to actually die? Check. Old mentor-san to guide the energy of youth? Check. Overly cautious (which in this case would have been reasonable) adult woman to contrast the power of youthful feeling? Check. World changing events that somehow have to have the main characters as the main cause and center? Check.
Bottom line: felt like a money grab, rather than an anime. Not that anime is not made for money, and not like most of them are not utterly crap, but it was like a toilet scrubber made of gold. So much potential wasted on an opaque and pointless story.