Use your mouse to move the paddle. Break the bricks with the ball. Upon breaking all the bricks, the game becomes more challenging.
Update: I made the ball glow when it breaks the blocks. Update 2: Wow, it's been over 6 years since I made this, and just now I decided to update it a bit. I added a lives system, decreased the starting speed of the ball, made it half as big, and cleaned up some stuff in the background. I still want to clean up some weird math and perhaps add a real title screen. I also added some comments to the code, so if you want to remix this it should be easier to know what each script does!