Defend the body from the invading viruses in this challenging Tower Defence game with 10 different maps. Strategically place and upgrade your towers to beat each level and unlock the next.
Place towers by clicking on a green square, if you can afford a tower it will be highlighted. Click on an existing tower to bring up it's upgrade menu. You must watch your avaliable funds or you won't be able to place towers as each one costs a different amount (and their upgrades too).