I like to describe it as Darwinist propaganda because its a funny thing to say and honestly its an awesome premise. It is your job to evolve through the various ages of life on earth. Become the strongest fish! Then, walk onto land and become the strongest Amphibian! Then become a Dinosaur and be forced to survive as a mammal during the ice age. Can you discover the key to evolve into a primate and use tools? Such an excellent game!