Featuring 25 single-player missions, three multiplayer maps, and additional buildings and units, the Emperor's Testament add-on offers an expansion of Perimeter's "Exodus" history, revealing the secrets of the lost Vice Frames and traces of a mysterious alien race. The game's single-player campaign follows the story of the Emperor as he discovers the Mechanical Spirit and new worlds, such as the Chain of the Psycho-sphere Worlds. Multiplayer action is available over a LAN or the Internet. ~ Gracie Leach, All Game Guide