Tail of the Sun

In Tail of the Sun, you start out as a caveman struggling to survive in the world. Hunt, gather, explore, increase your various stats, and eventually die. It's not just the usual game hazards of animals and drowning that can take your life, but also hunger and age. At that point you select a new member of your ever-growing tribe to continue on as. Your ultimate goal is to kill mammoths, and collect enough tusks to construct a tower that can reach the tail of the sun.