This demo is a level from the Defiance campaign - part of the Independence War Deluxe Edition product. In the Defiance campaign, you play an 'Indie' pilot fighting against the Commonwealth:

"You are Edison Hayes, the Captain of the Spartacus, a corvette class starship. Your vessel is part of the Independent Fleet (or Indies), which is waging a war of independence against the Commonwealth. The Indies are desperately short of ships. In a bold maneuver, Indie High Command has sent you and two wingmen on a raid to steal a Navy Cruiser from lightly defended Commercial Spacedock. Opportunities like this are exceedingly rare. However, things are never as simple as they first seem... "