To earn this achievement, players must evolve the symptom Neanderthal Regression, which, if evolved, will turn all infected into Neanderthals. It requires the Full DNA Repair trait to be evolved. Countries that are 100% infected will become ruled by Neanderthals, and cure research will stop in those countries. If the world's population is reverted back to the Neanderthal Era, the player will win the game and acquire the achievement. - 22.214.171.124. For further strategy, please see Strategy Guides/Frozen Virus.
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