Congratulations on your game. It looks nice, the scenarios are well worked, the story is good and it's informative, too! And yes, you did a good work on transmitting emotions; when I was on the street under the rain, I could clearly perceive Yuu's desperation.
I'd like to provide you with some feedback on things I think can be improved:
- There are 2 mistakes in the question about the square root of 64. One: I think it said "square route". Two: I think it asked for the square root of "√64". That's redundant; you should use "square root of 64" or simply ask for "√64".
- In the bathroom scene, is a bit unclear who says what because every message box looks the same and they are too close.
- The menu key... you should keep Esc working, too. The tip/explanation that appears when talking with the vending machine guy should be shown in the rain scene, too, or at the beginning of the game; you shouldn't rely on an optional event for providing the player with critical information (to me, this is critical because it wasn't obvious what the menu key was; using Esc is intuitive as most games open a menu with that, so you could not explain that one).
- I see that several people (including myself the first time I played) went directly to the storeroom and missed a lot of the content. I think that's because people may think that the content is unveiled along with the story, so they don't "waste time" going off the road if they already know what they must do. Perhaps you may move the storeroom to another location so the player actually sees the first floor before finding it?
That's it. Other than that, good work!