Hi thank you so much for your kind words!
The department store seems to be a relatively common point of confusion. We didn't have time to draw the clerk which probably is a contributor. However, you're just supposed to interact through the window on the left of the door.
The camera bug is known. however, I haven't yet implemented a solution for it. It all stems from the camera system using a stack, and when dialogue is entered, it will add a new position to the stack. However, if the dialogue is interrupted before it ends, that position stays in the stack so after the classroom scene it will go back to whatever conversation you were in.