text_a: does what a fine documentary does best : it extends a warm invitation into an unfamiliar world , then illuminates it fully and allows the larger implications of the journey to sink in unobtrusively .
text_b: the director 's twitchy sketchbook style and adroit perspective shifts grow wearisome amid leaden pacing and indifferent craftsmanship -lrb- most notably wretched sound design -rrb- .