Ah, I can see from the screenshot you did practice and then went to the orchestra and made 40 coins (you start with 50 and you have 90 in that screenshot). There is no play to the orchestra, it's part of the daytime management sim. You went, made money, and came back at the end of the day. When night fell the enemies attacked.
I can also see that all of your strings are broken there, and if you became exhausted that means you probably practiced too hard during the day and didn't sleep or repair your broken strings.
It looks like the game is working fine, you just weren't aware of what you were doing. In these old retro games, there were code limitations, so we couldn't put tutorial modes in... You just kind have to read the instructions or go it on your own and hope for the best.
Luckily, in the download there is a nice retro-style PDF manual that I worked hard on, so you can enjoy the game more by taking a look at that and getting the full 1980's game experience!