Thanks for the feedback. I will see what I can do about 1,2,3,4.
Will definitely add a volume setting in the next update. Right now, you can press 'M', and it will switch the game volume between 10% and 100%, but it was meant to be temporary, so I have not mentioned this anywhere in the game.
I do not know how to make music at the moment, but I do plan on learning this and adding it in eventually. (the priority of this is very low though, because right now I just listen to music in another program while I play this, and I think this is a better experience anyway)