Listen: Katy Perry's "Tsunami" & "Pendulum"

Unlike Rihanna, Lady Gaga or Beyoncé, Katy Perry's ascent to pop stardom is inexplicable. No doubt, her discography is littered with mainstream hits — Firework and Teenage Dream are fantastic, I will give her that! — but they are also... bland? Is it because they are just about transiently catchy? Or is it because there is a distinct lack of personality? It's a little hard to pin down, it's perhaps a mix of both. Rihanna may be a singles artist, but to her credit, they are hard to find fault with, sounding as fresh and killer as they were back then. The point here is that Witness, Perry's fifth studio album, is no different from her previous efforts. Embracing elements from house music, mainstream EDM, electro-tinged hip-hop and '80s new wave, she delivers a sonically flat album that finds her mostly chained to the rhythm, failing to stand out. And when she does, like in the chill Tsunami (reminiscent of Tame Impala's Currents and Rihanna's Same Ol' Mistakes) and the rousing gospel-funk anthem Pendulum, it soars.