Starhawk is the spiritual successor to the popular 2007 multiplayer only game Warhawk. It is not a direct sequel to that game but it has improved a lot of the same mechanics seen in Warhawk. It now includes a single player campaign and an improved multiplayer experience which allows you to build and maintain buildings along with a fast paced action 3ps shooter mechanics.
Here's a 12 minute footage of the game from G4:
Here's a 12 minute footage of the game from G4: