For a movie that was only 30 minutes long, it was really well-made. Even though it is so short, which means there's not much time for build-up and backstory, you still don't feel like there is much missing from the story, even though the potential for more development is, of course, here. The actors did a good job, I loved the friendship between Sumiko and Yukimi and I wouldn't mind seeing more of them. All in all, the only thing that was missing from this movie is more interaction between Sumiko and Mizu, but surprisingly, this didn't bother me at all. If anything, I enjoy the fact that their potential relationship was left open and for imagination. Also, I need to mention the music which was better than most high-budget films to be honest.
If you only have half an hour to watch something and you want it to be chill and wholesome, I definitely reccomend this one.