hey botu,
I just tested your game and I have to say: really excellent work!

But there are 3 things I noticed, that you should fix:
1. the ball passes through the walls from time to time
2. It would be cool if the bouncing direction wouldn't be randomised so much, because it's really annoying, if you aim for a block and it just bounces off into another direction.
3. if you have no balls left, you can still get to the next level, when you shoot the last bricks. then you get an extra ball with -1 lives.

Keep up the good work!
Scorpion