Earth 2140 Key

We are in the year 2140, and the Earth has nothing to do with what it was. Endless wars have left their mark, and the Earth's surface is decimated to the point where the entire population has been moved to underground cities.
There are only two world powers left, one controlling the East and the other based in the West. With fewer and fewer resources, another world war is inevitable. However, it seems that this could be the last.
There can only be one winner, fight for supremacy and see who comes out victorious on Earth 2140.