Classify given movie review into two categories: positive, or negative based on its content.

Q: this enthralling documentary . . . is at once playful and haunting , an in-depth portrait of an iconoclastic artist who was fundamentally unknowable even to his closest friends .

A: positive
****
Q: an inconsequential , barely there bit of piffle .

A: negative
****
Q: burns never really harnesses to full effect the energetic cast .

A:
negative
****