[John Mayer]'s early hits played up nostalgia, including images of running through his high school ("No Such Thing") and the novelty of physical exploration ("Your Body Is a Wonderland"). On his latest studio album, "Continuum," Mayer's lyrics delve into more grown-up matters, with several tracks alluding to the futility of war -- including the album's first single, "Waiting on the World to Change." The song captures his disenchantment and recalls classic Van Morrison with its bright, subtly accented arrangement and the supple texture of Mayer's voice.

That recurring incompleteness blurs "Continuum's" songs together, making his more adventurous sounds clash. The lively energy behind a cover of Hendrix's "Bold as Love" is tarnished by Mayer's Jimi-lite guitar solos, and the song's rock vigor sounds forced and out of place on an otherwise mellow album. Mayer may be striving for a more grown-up, adult-alternative sound but, ultimately, his bland songs fail to mature beyond lackluster college rock.