Sins of a Solar Empire is a science fiction real-time strategy computer game developed by Ironclad Games and published by Stardock Entertainment for Microsoft Windows operating systems. Sins is a real-time strategy (RTS) game that incorporates some elements from 4 differnt strategy games.
Rebellion adds new “Rebel” and “Loyalist” factions to each race, new capital ships for each race, new powerful, “Titan-class” starships for each Rebel/Loyalist faction, and smaller Corvettes. Rebellion also includes an improved engine.
Bellow you can see the release date and system requirements: