Noah Berger for The New York TimesMark Pincus, founder and chief executive of Zynga, announced new games Tuesday. Zynga executives held a press conference at the companys headquarters on Tuesday. They introduced several new games, including CastleVille, Bingo, Hidden Objects and a sequel to its early hit Mafia Wars, as well as new ways of playing old games.They also talked about something that might be even more significant to the companys future: a new playground that would leave it less captive to the whims of its partner Facebook.The larger game playing out here was Zyngas effort to redefine itself. Fifty-nine million people around the...