Alongside Tone Work's later VN, Gin'Iro, Haruka, this is one of the best pure slice-of-life moege I've read.
It's hard to summarize the things that make this VN so good. The premise is ultimately fairly simple - the protagonist moves back to his old hometown, and meets a bunch of girls, all who have very strong passions, dreams, and in some cases issues/insecurities. They get to know each other as they realize how much fun they have working towards a common goal - specifically, preparing for for the school's Tanabata festival. Ultimately, the protagonist gets involved in directly supporting the dreams of the chosen heroine. While the premise is simple, the execution is near-flawless.
The character writing is fantastic and balanced well across all routes - the cast is exceptionally well characterized, with personalities that are fun to read both on their own, and interacting with each other.
The core storylines are also very well done for the most part. My overall route rankings would be Rikka > Natsuki > Sora = Misa > Touko > Marika - that said, the middle 4 are very close in quality, and the differences in their ranking are mostly just subjective preference (eg. I mostly have Touko second-to-last because I don't really gel with her initially flighty personality). Aside from Marika's route, I would say all other routes are among the best the moege subgenre has to offer.
Rikka's route is clearly a standout, and has far more content both in the core route and the After than the others. She has the deepest character development, and hers is the only route to introduce an entirely new major character (complete with character sprites). It was written by the same person who wrote Mizuha's route in Gin'Iro Haruka, which unsurprisingly is my favorite route in that VN as well.
I didn't like Marika's route as much as the others - I felt it had the weakest story, and was full of annoying cliches. She's a pretty typical "childhood friend"-type character, but more specifically she's the kind that has been in love since childhood (with said love, and her childhood infirmity, being her main defining traits). I also found the main non-Tanabata point of contention in her route (especially her After) to be very annoying/cliched - basically, the "overbearing father" trope (ie. "you ain't good enough for daddy's little girl"-type character). It's not a terrible route in the grand scheme of things, but it felt disappointing when directly compared to the other routes in the VN.
The art is top notch and the music is solid. The character designs and art are all very cute and distinct (even the two characters who are joked about in-universe as being physically similar, Natsuki and Touko). There are no animations. H-scenes are standard for Japanese VNs (just mostly variants of a static image).
Overall, this, or Gin'Iro Haruka, are probably the first VNs that would come to mind if I were asked to recommend a moege. Hoshi Ori would come to mind first though, since it is fully translated at the time of writing this review.