I like the basic concept, it could be integrated into some larger puzzle game.
You can also think about variations like removing the objects that have already been used.
It took me a bit to understand the "billiards" controls, where I think the distance and angle of your click determines the power and makes the ball shoot off towards the oppsosite side. An indicator would help a lot (like a line from the ball pointing towards the shooting direction, increasing in length when further away)
Also it's still possible to add balls while on the restart screen, which breaks the game.