From the homepage: The world of Darwinia is a virtual themepark,
running entirely inside a computer network and populated by a
sentient evolving life form called the Darwinians. Unfortunately
Darwinia has been overrun by a computer virus which has multiplied
out of control. Your task is to destroy the Viral Infection and
save the Darwinians from extinction.

WWW: http://www.introversion.co.uk/darwinia/