The 3D real-time strategy genre has come into its own only relatively recently. Older games such as Battlezone and Warzone 2100 showed that it was perfectly feasible to integrate the gameplay of classic real-time strategy games into a 3D environment. But 3D real-time strategy games continue to rapidly improve, and developer TopWare's Earth 2150 provides further evidence of this trend.

Earth 2150's plot might be improbable, but it sets up an interesting premise for the game: The global market has disintegrated, and war has ravaged the land. Out of the ashes come three distinct factions - the United Civilized States, the Eurasian Dynasty, and the Lunar Corporation. The United Civilized States comprises a decadent society whose workforce - and army - consists solely of robots. The Eurasian Dynasty founded its military technology on 20th-century Russian tanks and helicopters that were scavenged after the Holocaust. The Lunar Corporation is a faction that colonized the moon to avoid the impending disasters on Earth, and its technology surpasses that of the other two factions. A series of nuclear attacks knocks Earth slightly out of orbit, enough so that it's on a steady collision course with the sun. Time to get out. The goal of the game becomes a race to mine enough resources to build an enormous evacuation ship and eventually colonize Mars. Unfortunately, there are only enough resources for one faction to accomplish the task. Time to eliminate the competition.

You play through the single-player missions in Earth 2150 as one of the three factions. In the single-player game, each side has a main base area that's safe from the enemy. Here, you can create structures and units as you do in the mission scenarios, and everything stays in place for the duration of the game. In fact, you can transfer extra resources and units back and forth between your current mission and the main base. This makes it possible to salvage unused resources and surviving units at the end of a mission. When a mission has ended, you can return to the main base area, repair troops, manufacture troops, research new weapons, or allocate funds to the Mars evacuation project before you head on to the next mission. The end-all goal is to get to Mars, and you're updated periodically with messages on your fund-raising progress.