I finished the VN! I was able to see all the endings! I really like the message and you should be proud you were able to tell it with the stringent conditions!
I no longer have to worry about school, thank goodness. But I can relate to that feeling of wanting to pass more than wanting to learn. I felt that in university, especially. Your portrayal of that feeling was nicely done. I love the ambience of the clock ticking. I thought that was a perfect choice. It brought back the dreaded test mode feeling as I played.
Also, your UI design was very nice! I liked the thought bubbles as choices. It added to the immersion, I feel!
Wonderful job on O2A2 and congratulations again for completing it! I hope you continue to create and tell your stories!