With the small cat use you arrow keys to dodge the ball. If the ball hits the cat (you) 10 points will be taken away from your score. Also you get points for the ice cream ;P it is quite hard when it gets up to three balls. By the way it goes on forever :D
I used some ideas from Scratch Programming In Easy Steps. By the way check out @~firefox~ and neeena they are a friends from school :P