For her second album, Katy Perry took her new star status as a cue to explode outwards in every direction at once. Everything is day-glo bright and pin-sharp, even in the moments of pained introspection (“Who Am I Living For?”) amid the sloppy party anthems (“Last Friday Night”), silly sexiness (“Peacock”) and nostalgic trips back into teenage heartbreak (“The One That Got Away”, “Teenage Dream”). So rather than tone down her eccentricity, she adds even more sparkle, colour and complexity to that cartoonish persona.