Something old, something new, something bladed, something blue: Look for all of these and more in ''X2,'' the latest installment of director Bryan Singer's comic-book saga of social oppression, minority pride, and battle-applicable birth defects (opening May 2). And things have gotten considerably darker: ''It's kind of a trial by fire for Mutant High,'' says Singer. ''Literally, in certain scenes.'' Below, what every good citizen -- mutant or norm -- should know about the impending fray. Consider this your spoiler alert and warning: Even as you read these words, Fox executives are looking at an initial print of the film -- thus, everything you read could undergo serious mutations before the premiere.