From the in game instructions: Use the mouse to control the cat around the screen and pick up all the dropped food. The quicker you grab the food the more points you get for it. Wandering pedestrians move only when you move - if you stay on the same spot nobody will move. As you progress more and different types of pedestrian will appear, as well as other strange things designed to hinder your food-munching progress. Picking up the glowing white balls will allow your cat the ability to push pedestrians outwards away from him in a radial manner by clicking the left mouse button, but you can only keep up to 3 of these pickups at a time so use them sparingly.