Ur a law man, the best kind of law man; you're out to get real nasty bad dudes, and it all happens at a microscopic level. These bad dudes are diseases, the slimey, jiggly, wobbly kind. They will make the person they are in sick as dog, maybe even sicker. So you've been tasked in this action-shoot'em up game with eliminating the diseases and their bosses before they end up killing the person.
Aim true, shoot fast, collect weapons and
unlock weapons and upgrade like crazy. The diseases get worse, and as a result you have to get better, smarter, faster, stronger, and better armed. You, my friend, have a very important job. As the body's law enforcer, you need to keep the person alive. R U up to the task or do I go get someone with bigger cubes than you? WELL?