I just finished reading Harmonia and boy, it was kinda disappointing ngl I was expecting more from Key, but it just felt like they recycled a lot, from the art (I know it's the same artist, but still-) to the plot. Even though I know it's the same artist as their other vns, it felt very generic when it comes to Key's works.
There were two main things I HATED in this: the writing and the voice acting. The writing was just so damn plain it hurt. I know he's a robot and all but I don't know, they could have written it better; the voice acting was painful to listen to, oof- I tried to, but I had to mute all of their voices;;;
Overall, I'd give it a 7/10. It wasn't anything special, but it was a nice little story, good enough not to be a 6 or lower.
I'll probably read Soundless next!