In Tail of the Sun, you are a caveman in prehistoric times. Your mission: to build an ivory tower of mammoth tusks tall enough to reach the tail of the sun. You are to develop your caveman tribe by hunting, swimming, running, climbing, and taking on other activities to raise your physical or mental attributes. You must venture off into a vast, untamed world to explore harsh terrains that consist of deserts, caves, forests, and ocean floors.
The player's ultimate objective is to build a tower of mammoth tusks that reaches the sun. To this end, he or she must gather enough food for the tribe to thrive and multiply, while exploring a large map full of various creatures and oddities.