 Author Simon Leng describes the melody of "Beware of Darkness" as "complex and highly original".The melody of the verses incorporates a pedal point on the key of G major and moves to G sharp minor, a progression Leng claims "should not work in harmonic terms", using as an analogy a count of "one, two, six", but notes that somehow the melody manages to work.Music professor Wilfrid Mellers explains the effectiveness of this key shift as dramatising the "beware" in the lyrics.