You need to slide the paddle with the mouse pointer, and break the bricks. Game over if you don't catch the paddle. I apologize that the game doesn't look too well, but the book with tutorials that I have doesn't provide very good instructions for this game and Scratch has an error that doesn't let me put sounds. :(
It may look a little hard, but try to play it a few times and then it will look easier. If it's a bit laggy, I can't do anything about it :( it's the code. Feel free to remix. I'd like to see that people add more color schemes to the remixes they make :) it would be nice to have more color variants.