You must navigate a nanobot through a 3D environment of blood vessels and connective tissue in an attempt to save an ailing patient by retraining her non-functional immune cells. Along the way, you will learn about the biological processes that enable macrophages and neutrophils – white blood cells – to detect and fight infections.
Immune Attack is free. When you go to the download page, they ask you to donate and register, but you do not need to do either. Scroll to the bottom of the page to download without registering.