It's insanely hard!! haha! But you can do so much with the assets and the gameplay, maybe turn it into some sort of traffic control game. The notes mechanic made it too unnerving, like you had to be on the edge of your seat trying to hit the notes while controlling the cars, it was too much. But maybe if you remove the notes you could have a chill traffic control game where you avoid cars colliding for a certain amount of time and you add more and more cars as you progress the levels.
I like the concept of controlling cars with a whistle though, the art is cool and the music is good too (despite what I mentioned about the notes mechanic). Good job!