I really enjoyed this! I'll break down my thoughts.
~Art~
Absolutely lovely. The character designs were all super interesting, the animations were great, the backgrounds were colorful and fun to look at with lots of little details, and the textbook was of a kind I hadn't really seen before. One note on the textbox, the font sometimes jumps out of the textfield, so I think shifting those parameters just a bit would help.
~Story~
The story was really interesting. You learn more about the world the more you play. The overall introduction was a bit slow for me, and some of the exposition felt a little clunky, but once the story really got going that lessened exponentially, and the details were given in smoother way. Things like Sally's obvious reluctance to speak of her true feelings about her master, Acid's origin and motivations.
~Writing~
This was probably the weakest aspect in my opinion. I prefer a mix of narration and dialogue though, so it could just be me. Putting the actions in *asterisks* felt a bit silly, especially at the more tense moments. However, it didn't take too much away from the overall game, and by the end I enjoyed it more.
Congratulations on finishing NaNo and thank you for the lovely game!