Thanks to the excellent NotExactlyRocketScience blog for posting the link to this game. Pandemic II is a complex flash game based on strategy, evolution (though more like design) and the spread of disease. The premise is simple – take a pathogen (bacteria, virus or parasite), and watch its spread across the globe. Along the way you can alter the pathogen to change its properties, making it more infectious, more lethal or less noticeable. The aim of the game is to wipe out the population of the world.
It is easy to save using Firefox add-ons.
Check out the game here: http://www.crazymonkeygames.com/Pandemic-2.html
And the tutorials here:
Have a go!