Duff described the album as "pop music has some more rock and edginess to it"; she said the type of music was "somewhere in between" pop and "hardcore rock", but that she did not know how to explain it. According to her, there is "a lot of different music" on "Metamorphosis" that she finds difficult to categorise. The music on the album is "a little different" from her previous music because, according to her, the album "has all the kinds of music I like to listen to". She said that there are many "different sounds" on the album, such as rock and electronic, and "a whole range" of tempos, including "deep, slow" tracks and "high-energy" songs to provide her with a "boost". According to Duff, everyone experiences varied feelings and moods, and they can "feel a bit better" by playing their favorite song.