It's also a technical tour de force, they turned shaky black and white footage with variable frame rate (from early hand cranked video cameras) into almost-cine

It's also a technical tour de force, they turned shaky black and white footage with variable frame rate (from early hand cranked video cameras) into almost-cinema-grade color footage, and they recreated the sound using speakers local to the areas of the soldiers, combined with lip reading. It's an incredible work.