Use your mouse (or touchpad) to control the blue circle. Collect green circles. Watch out for red circles! Green circles collect one point each. Red circles collect -3 points. Collect more than 25 points to win, less than -15 to lose. Red circles don't harm you when they are still.
I got the idea from a book. Now, a little bit harder! You change size based on your points, so try not to get stuck in a corner. New additions coming soon! Tell me of anything to fix in the comments