Has Potential
But it definitely could use some more gameplay elements. First, there is no real incentive to click on multiple balls, as a combo causes the same amount of retreat as just clicking on a single. It would be a lot more fun if the combos, in addition to giving a higher scorer, caused a larger amount of retreat for all of the balls on the screen.
Also, the game could use some specials/powerups. Some that might work would be freeze time, reverse gravity, larger targets, slow time, add shield, increase (raise) defense bar, etc.
It would be nice too to add some different backgrounds and/or music.
Finally, the music loop during the instructions has a break in the sound and should probably be changed.