Over the past few days, I have been slowly adding more and more music and sound effects to the game.
So far, all the levels have the same music. But different "worlds" will contain varying music to fit the theme. Currently, there are 5 music themes to suit the five currently implemented worlds and their containing levels.
Preview of Level 1-1's music: Drive.google.com
As far as the sound effects go, there are still many to be added, and so the next few days will be dedicated to the addition of more, if not all, sound effects. After this is achieved, a working demo of the game can be released.