In Bio Hazard Battle, you play as one of the many soldiers fighting for the United Nations in an attempt to stop a dangerous virus from spreading. The game is a side-scrolling action RPG, with you using your weapon and magic to fight off the enemies. There are a variety of enemies to fight, including aliens, mutants, and zombies. The game is set in a variety of locations, including a research center, a military base, and a research lab. You can also use your environment to your advantage, by using destructible objects to your advantage. The game is set up so that you can play as many campaigns as you want, and you can also multiplayer with friends.