Allegro, which concerns a son following in his father's footsteps, represents a "musical experiment" conducted by Rodgers and Hammerstein. Defying "virtually all musical theatre conventions" of the time, its Greek chorus frequently interrupts the narrative, and the show focuses on a larger theme of personal struggle in the face of success. Minimalist in its staging, patterns of light were used to represent both spaces and emotions.
However, many critics disagree as to Allegros status as a concept musical, stating that the linear nature of the plot continues regardless of the choral interludes. The show was a critical failure, which many theatre historians blame on the inexperience of director-choreographer Agnes de Mille. Disheartened, Rodgers and Hammerstein returned to a more traditional format.