Sins of a Solar Empire is a 2008 science fiction real-time strategy video game developed by Ironclad Games and published by Stardock Entertainment for Microsoft Windows operating systems. It is a real-time strategy (RTS) game that incorporates some elements from 4X games; its makers describe it as "RT4X". Players are given control of a spacefaring empire in the distant future, and are tasked with conquering star systems using military, economic and diplomatic means. The game was released on February 4, 2008, receiving positive reviews and multiple awards from the gaming press. Its first content expansion, titled Entrenchment, was released as a download on February 25, 2009, and its second content expansion, titled Diplomacy, was released as a download on February 9, 2010. A package combining the original game with the first two expansions was released at that time, with the title Sins of a Solar Empire: Trinity. A third expansion, the stand-alone Rebellion, was released in June 2012. A sequel to the game, Sins of a Solar Empire II was announced on September 16, 2022. Gameplay Sins of a Solar Empire is a space-bound real-time strategy game in which players control one of three different races: the industrial TEC, the psychic Advent, or the alien Vasari. The playing field is a 3D web of planets and other celestial objects in the orbital plane of one or more stars. The game features a sandbox mode, allowing the player to choose different types of solar systems to unlock achievements. Players can conquer neighboring planets and explore distant star systems in a "massively scaled, fully 3D environment featuring entire galaxies, orbiting planets, clusters of asteroids, space dust and radiant stars." Notably, there is no single-player campaign mode, but games can be played against AI opponents offline and other players online. Ironclad Director Blair Fraser asserted that the game's Iron Engine is specially designed with technologies that allow it to handle very large differences in size, scale, and distance. Resources and structures Sins of a Solar Empire has three main resources to gather: Credits, Metal, and Crystal. Credits are the general currency used by the three races in the game, and are gained by completing missions, collecting bounties, creating a trade network, and taxing planets. Metal is the most common resource in the game, and is gathered by building extractors on metallic asteroids; it is used to construct basic ships and structures. Crystal is