Aya Hirano's a bit of a dividing presence among J-pop fans. While her high-energy formulaic work has made her a huge number of fans, her endless vibrato and overpowering rock backing have alienated just as many. On Riot Girl, there's a mix of old, new, and remixed tracks from the last few years, all providing a different look at the same underlying creature. After a frenetic opening where the arrangement tends to overpower Hirano's vocals, she starts to hit her stride with some straightforward girl-rock in "Hero." This is probably where Hirano works best, though not necessarily where she's been most successful. While in these limited cases she can work within the structure of a basic pop melody, she tends to go full-bore instead, guitars and drums blasting, vocals screaming, and vibrato aflutter. Case in point: "Ashita no Prism," with a sludgy front guitar that just barely allows Hirano's screams to be heard. There are a few nice little surprises here however, bucking the trends set by Hirano's back catalog and the bulk of the album. "Breakthrough" is a gem of a little modern ska number. Though Hirano's vocals are a bit overpowering for their purpose here, the arrangement is thankfully light. There's also one light ballad toward the end, showing a side of Hirano's vocals that simply isn't commonly heard. But that side isn't bad at all. Riot Girl will do much the same in a small form for Hirano's listeners as her larger body of work has done in the past -- fans will happily devour the new material for exactly the sound that they've come to love, and detractors will happily ignore the material. Newcomers to J-pop should likely look elsewhere for their first fixes however, as Hirano is an acquired taste, evidenced by the music on Riot Girl in particular.