Supreme Commander 2 is a real-time strategy (RTS) video game. In both the skirmish and multiplayer modes, players start out with an Armored Command Unit (ACU), which is a large, powerful, construction-capable unit, as their avatar on the battlefield. They build mass extractors and power generators, which produce mass and energy, along with research facilities that produce research points faster. The ultimate aim of the game is to destroy the opponents' ACUs.

Twenty-five years after an uneasy peace settled over the galaxy, the assassination of the newly elected Coalition President shatters the fragile alliance between humanity's three great factions — the United Earth Federation, the Aeon Illuminate, and the Cybran Nation. The story follows three commanders drawn into the unraveling conflict: Dominic Maddox, a UEF officer torn between duty and his Illuminate wife; Thalia Kael, an Illuminate warrior fighting to restore her people's glory; and Ivan Brackman, a Cybran clone serving his creator. As their paths cross, they uncover the machinations of a mysterious operative named Gauge and the secret of "Shiva Prime," an ancient device with the power to reshape worlds and reignite total war.