Lol, when I read the other reviews, I got curious because they said they liked the chemistry between Ruri and Nagi, so I was under the impression that they're of the same age. So I was pretty confused when I saw Nagi ahahah. Anyway, animation-wise, it's pretty good. It's really pretty, especially when it comes to the crystals, although it's a bit leaning on the fanservice-y kind sometimes when it comes to Nagi. But well, it's not really an issue for me. Soundtrack-wise, I was pleasantly surprised at how chill it sounds, especially the opening song. I have a habit of skipping them after listening once, but I think I'm gonna be very happy listening to its opening song for all the eps. As for the writing, I'm honestly pleased about it. The pace is pretty good, but the explanations in between really carry the episode. As someone who writes for a sci-tech magazine, this is really helpful and quite knowledgeable. I'm glad I picked this anime up.