Chameleon need to eat flies there are in two sides, left & right, in the start screen. Chameleon conforms its color with each fly that eats it. There is a time bar on the top of the game screen & you should pay attention to it when you are playing. By eating each fly you earn score. Chameleon shouldn't miss any fly to eat otherwise you lose the game. Step by step the speed of the game starting to increase. Heave fun!