Background story
A short but fragile period of peace followed the cold war. Humanity is divided into two factions. The western part under the leadership of the USA and the eastern part under the leadership of Russia.
That peace ended shortly after the beginning of space colonization. Under the continued pressure of the hegemonial western faction on Earth, large parts of the eastern factions left Earth completely and moved to Mars and are now known as Martian.
Gameplay summary
In TerraMartis4x you take the role as leader of one of the factions, either Terra or Mars. Both factions are at war over the uncolonized space. Your goal is to lead the faction of your choice to victory.
TerraMartis4x is divided into two layers. On the galaxy map you make strategic turned based decisions about which planets to colonize, which fleets to build, where to attack, what to defend and which planet to conquer. When two fleets meet you can dive into the battlefield the second part of the game where you make tactical decisions for each unit in your fleet in real time.
Beside the two larger factions Terran and Martian there are also some minor factions in TerraMartis4x mostly from the outer asteroid belts and not recognized as a united faction by the former two.