Katy Perry , a big miss

analyzing Katy Perry's Thursday concerts, from the props that dotted the stage (an oversize cat head, with glowing blue eyes, and an assortment of giant blowup strawberries and bananas) to the oddly phallic, inflatable lip balm the singer wielded on "I Kissed a Girl," seemed ripe for psychoanalysis.

Perry, wearing a sparkling mini-dress that made it look as though she had rolled around in crushed glass, opened her set with the propulsive "Fingerprints," stomping her electric blue heels as she sang, "I gotta make my mark." Indeed, the 24-year-old has done exactly that, releasing a string of hit singles that have kept her major-label debut, "One of the Boys" (Capitol), on the Billboard charts for the last 40 weeks and counting.

But aside from a handful of tunes that offered genuine pop thrills (particularly the oddly infectious "Hot N Cold"), Perry struggled to find her footing. Her vocal shortcomings, obvious from the get-go, leaped to the forefront when her four-piece backing band—decked out in white suits that looked pilfered from Tom Wolf's closet—departed, leaving her alone onstage for the acoustic "Thinking of You." Even worse was an attempted Queen cover. Though Perry had the outfit down (her full-body, leopard-print cat suit looked like something Freddie Mercury would have flaunted for a packed Wembley Stadium), she couldn't match the flamboyant frontman's vocal prowess on her atonal version of "Don't Stop Me Now."

While few of Perry's songs even push PG-13, her between-song banter frequently slipped into rated-R territory, the singer reveling in off-color humor like a middle schooler who has learned a new dirty word. These salacious tidbits, which some might have found humanizing, came across as overly calculated—a manufactured pop princess' callow attempt at displaying edge.

If anything, her songs could have used that extra bite.

Just check the surprisingly tame lyrics of her oh-so-risque hit: "I kissed a girl and I liked it/I hope my boyfriend don't mind it."