Irvine-based Blizzard Entertainment said Wednesday that the firm has launched a beta test of the firm's real-time strategy game, StarCraft II: Wings of Liberty. The new, massively multiplayer online game is a sequel to the firm's 1998 strategy game StrCraft. Blizzard said it expects to ship StarCraft II: Wings of Liberty in the first half of the year, and has invited thousands of gamers to provide feedback on the firm's beta.