The goal of the game is to zombify or kill the whole world. There are 24 countries. Countries will fight back with their armies and shut down to protect themselves. Zombies spread by land, sea, and air. Upgrade your zombies using the upgrade tab to make them more dangerous. Upgrades are in a skill tree with weapons being beneath the tree. Weapons only upgrade killing power while skill tree upgrades the way zombies spread and killing power. To check on the world status click "world info" from the in game menu. To navigate around the map click and drag it. The 3 small circles are game speed. Points are gained on humans killed and time passed.
To change the map (from satellite to cartoon and back) use the in game menu