Thanks! These are really good suggestions.
Mouse problem was something I noticed myself and I was going to fix it, but in the end I did not have enough time. As a quick fix, I changed the mouse cursor visible, which was something that was also asked. That maybe should help a little.
I added some sounds to the game in the update, but did not have much time to work with them either, so they are quite simple. If I'm going to make updates to the game later, I'll definitely add the blackboard sounds!