An alien virus has contaminated most of the population. You have to inject a single genetically modified infected cell into various locations in a patients body to cure them. Any cell which touches your engineered cell will itself become infected. Any that touch those will in turn be infected, and so on. You must infect and destroy a growing number of cells in each location.
There are special cells already in the body which, if you are lucky enough to find, you can use to help you - such as ones which slow the cells decay or make them grow to a larger size.
The full game is available for FREE but if you enjoy it, please tap the link on the title screen and donate to Cancer Research UK. Any amount, no matter how small, will help them research treatments and cures for cancer. My JustGiving page is at:
The game features a leaderboard across all formats which will give your world ranking.