A Tower Defense Game, Literally

This is a generic tower-defense game, but instead of being top-down, it focuses more on side-scrolling part. Story: Its year 2756. Humanity was on the verge of finding the cure for death, an antidote that would make any human immortal, but the mishandling of this antidote made it into a virus that would make its host an undead creature hungry for flesh. In only 50 years the virus has spread so fast that only a handful of people were still alive. Those remaining few have gathered into this place,...