Creatures is a biological simulation. You start with six eggs of Norns, cute little creatures who live in an imaginary world. Your task is to give them knowledge about the world they live in, teach them how to speak, how to use toys or an elevator, how to eat, and so on. They will eventually grow older, reproduce and die. The game uses its own genetics system, as well as biochemical and neurological calculations to determine the evolution of Norns and the way their DNA would develop in their descendants.