Minor fixes to:
Some players have also reported trouble with accessing Kuna'a and Aisa's routes. If you are experiencing these issues, please try uninstalling the game and reinstalling it (some people have had to do this multiple times). Do not use old save files when trying to access Kuna'a and Aisa's routes either.
To unlock them, you must play from the beginning and make sure you go on their date in Chapter 3 (go to the flower festival alone and then choose to either make a bouquet for Aisa or rest for Kuna'a). After that, their respective route will unlock for that save file (bouquet unlocks Aisa, resting unlocks Kuna'a).