The Style IS the Substance
Some sequences stand as lessons in directing/camera placement/editing. Friedkin has this one-of-a-kind, gut-level understanding of the form.
For example:
The introduction of the Serbian commander. He is first glimpsed through the muzzle flashes of his men's rifles as they exterminate a group of villagers to his satisfaction.
The slaughter of the hunters/sweepers. We hear the screams of the second hunter over an abstract shot of a figure (Hallam) walking towards camera through the brush.
LT entering the woods for the first time and spying the hole in the sapling made by Hallam's knife. The cross-cutting between the zoom-in on the hole and the zoom-in on LT's eyes.
Hallam's questioning at the FBI office. Every angle is canted slightly. Hallam is the master of this domain despite being the prisoner. Reality itself is off-balance.