Cats love boxes! Launch cats of different sizes into the box. If two cats of the same size touch each other, they merge into one larger cat.
In the game, you can also use the mouse to drive any cat out of the box. Also, from time to time you can catch mice that give this opportunity.
Try to unlock all the cats.
Click anywhere within the box to launch the cat there. Cats of the same size merge with cats of the same size to form a larger cat. Use mouse to delete cat from box.