Virus is attacking your body, protect your body cells, kill all viruses as many as you can.
There are various viruses that attack your body, you must use different guns to kill different viruses.
Try to avoid the virus, use a shield to protect yourself, but the shield only lasts for 20 seconds, use as well.
Hang on for 120 seconds to get to more difficult levels.
Enjoy the game, winning every level