This short film is only available for viewing at the Studio Ghibli museum in Japan. Additionally it's screened in Japanese without English subtitles. As I only know a few Japanese phrases, I had to follow along with visuals alone.
That said, the visual art was very impressive. The story focused around a boy planting and fostering a miniature planet which allowed for several interesting effects. An artificial atmosphere was creating by spraying water on an initially lifeless, rock-like planet. Animations involved careful depiction of weight as affected by gravity in the atmosphere of the planet. There were a few shots using a fixed perspective from the
rotating planet. Night shots made great use of light beams and casting shadows.
Characters designs felt reminiscent of other Ghibli films, notably Howl's Moving Castle and Porco Rosso. There were a few cameos from other films too.
The world building featured more sci-fi elements than other Ghibli films. A majority of the film was narrowly focused on the residence the main character stayed at. There were a few short scenes showing a bustling, futuristic city which would be interesting to see more of.
I'd love to see this again with English subtitles to gain a better understanding of the story.