Kevin Mears’s review published on Letterboxd :
A slog. Jumped around all over the place, making it pretty hard to place any timeline of action and keep track of any drama going on with the characters. Maybe that was intentional to reflect the chaos of battle - If so, didn't work for me. The Island scenes were played out to reflect the full horror of the battle, but there was no sense of the duration and unexpected resistance that made the whole battle so sobering and iconic.
The parts where the film tried to explain the significance of the flag in the American psyche were only partially successful, and the voice over seemed like an admission of defeat on that front.
All very puzzling since the companion piece Letters from Iwo Jima was really good.