Watching «Every Little Step,” a new documentary by James D. Stern and Adam Del Deo, is a bit like walking through a hall of mirrors. Life imitates art, art reflects life, and after a while the distinctions threaten, quite pleasantly, to blur altogether. The film follows a group of mostly young dancers and singers auditioning for parts in the recent Broadway revival of «A Chorus Line,” a musical which is itself built around the auditions of 17 mostly young Broadway-besotted dancers and singers. The premise of «Every Little Step” is no less inspired for seeming so simple and obvious, and it pays tribute to the durability and continued relevance of «A Chorus Line,” which first opened in New York in 1975, before many of the performers in the movie were born. — A. O. Scott, The New York Times