The autobiographical “Opening Doors” provides a glimpse of the struggle for recognition as three fledgling musical-theater writers sing of their efforts to break into legitimate showbiz. Lapine films the song as a retro-styled Technicolor movie-musical insert, using split-screen and rear projection to capture the bright lights of Broadway and the dizzying heights of New York. As the green kids with stars in their eyes, Darren Criss, America Ferrera and Jeremy Jordan are as cute as a box of puppies, getting an able hand from Broadway regulars Jackie Hoffman and Laura Osnes as auditioning performers. The chief delight here, however, is Sondheim himself, winking at the audience in an extended singing cameo as a cynical producer.
Six By Sondheim: TV Review (The Hollywood Reporter)