Virus Evolution is a free puzzle game.  Being sick sucks. But imagine that sickness, that virus, had figured out how to evolve and grow in intensity as it cycled itself through your body. As the virus merges with other viruses and other iterations of itself, it rushes through your body and wears you down as it builds itself up. Slowly becoming more and more powerful as you become weaker and weaker. It is a sad but common story.