‘Sia: Nostalgic for the Present’ Review: A Concert Performance Film from 2016, but It Channels Sia’s Mystery and Power

Sia’s top songs, similar "Unstoppable" and "Titanium" and "The Greatest," are anthems of strength, power, fortitude, invincibility, and watching the movie it’s fascinating to behold however her facelessness feeds that quality. She’s an abstract figure, a brace of lips singing, and this creates the sensation that the powerfulness she’s singing astir doesn’t emanate from her. She’s channeling a unit larger than herself — the rising specter of feminine triumph. She’s simply the vessel.