In the sequel to Earth 2140, the use of nuclear weapons have pushed the earth out of its normal circulation around the sun. Earth is coming closer and closer to the sun. The whole climate changes. The three "states" left on Earth (and the Moon) try to conquer the areas which contain the resources necessary to build a huge spaceship to escape from earth.
In total, there are 70 missions of non-linear real-time strategy gameplay to complete. It features a range of land, air and sea units, with some able to 'dig' tunnels through mountains so that units can drive through it. There is also a level editor.
The game's 3D engine has realistic weather effects like fog, rain, thunderstorms, etc. The physics engine is detailed, too. For example, if there's a crater somewhere and it starts to rain, the crater slowly fills with water. When the sun goes down and it gets dark, all units and buildings have lights on them.