Great music, great writing. The art and all the various portraits are super lovely. Having you make choices at crucial points using only emotions was very clever. Alas, despite my honest picks I didn't get a single good ending in my first run, and the normal endings weigh heavily on my heart. At least they were rather hopeful -- I left with an impression like "well, they'll figure it out eventually". While I've become much less of a completionist over the years, I went back today (I played yesterday) to try to get some of the good endings and I'm pretty happy with how the stories are resolved (only missing Wrigs' now). But damn. That choice at the end was so hard to make the first time!
I gotta agree with Kevin regarding the backgrounds -- in fact, at first I thought Wriggle's chapter had taken up the entire day. I wouldn't know how to show the passage of time during the day, though. Hmm...
Back to the story, I was pretty neutral towards Kokoro but this made me like her a lot more. I also really liked Ichirin here and her interactions with Kokoro. Certainly something I hadn't considered before. There's something to say and take from every scenario, honestly. Wriggle and the gang, figuring out things. Aya's development was quite surprising and written very well. And finally the Prismrivers seemed like a fun bunch each with their own unique and varied opinions about art and music. Everyone opening up to Kokoro and showing their vulnerabilities... it's simply good to read a story like that.
p.s. regarding the music, I'm a sucker for chiptune so I gotta mention Cirno's theme in particular. Very good chiptune in a hella sweet C64 (I think... or Gameboy?) style.