Amazing to still see flash game in 2026 lol. Very interesting premise, and really suits the style of your art. The B.A Shiori on your thumbnail captivated me as well! Just curious though, is the B.A Shiori a reference to anything? I feel like there is a deeper meaning to the story you've written, but I don't think I'm smart enough to figure out >_<.
Music and sfx are extremely important, and it happens to park under the same "ambience" category. Do not let your effort of making good visuals get pulled down by lack of audio. Sfx takes more effort and time so maybe you can do that only if you have enough time, but you can probably find bgm that suits the mood of your game and include them in within 30 minutes. Here are some that I think may suit your game:
https://peritune.com/blog/2019/01/19/wonder6/
https://peritune.com/blog/2018/07/09/whisper3/
Good job! Thanks for making this!