Impossibly beautiful, incredibly smart, surprisingly candid and fiendishly calculating, the Madonna of Truth or Dare is adept at soaking up every inch of the spotlight. Director Alek Keshishian’s documentary about the singer’s Blond Ambition Tour purports to offer a closer look at the Material Girl, but her media sophistication is too formidable, making us always question who’s the “real” Madonna: the savvy businesswoman or the needy brat. What’s not in dispute, however, is that her eye-popping, ear-candy concert performances slay.