Scratch project: bouncy ball game

I made a simple pong- or brickbreaker-style bouncy ball game in Scratch, which I think would be a good project for the kids. You can see it at

Use a mouse to move a paddle and bounce a ball around the screen. You have 5 lives; if the ball falls off the bottom, you lose a life. Your score increments - watch the high score to see your best achievement in your 5 lives.  As you increase in "levels", the ball gets faster and the background and ball color change. There's also some simplified physics of changing the ball's angle if you hit it with a moving paddle. Steps for getting the students to implement it:
  1. Make a ball sprite that bounces off the walls.
  2. Add a paddle that follows your mouse horizontally, but stays in a constant y position.
  3. Make the ball bounce of the paddle if it hits it.
  4. Stop the game if the ball falls off the bottom of the screen.
  5. Enhancements:
    1. Add a score counter
    2. Make the ball speed up every 30 seconds
    3. Add 5 lives
    4. Add levels with different backdrops
    5. Add a high score counter
    6. Add some kind of boost if you hit the ball with a moving paddle
    7. Any other ideas...?