Some of its strength is in Mel Gibson and Ray Winstone, both in their acting and characters. It has kind of a pared down straight-ahead quality that moves the story forward. Gibson's thinking is advancing as the story goes and we see it in new scenes as opposed to having it explained to us verbally, and this is refreshing. Winstone's character is concocted and an amazing invention, but it does distill a picture of a state that covers up its errors and its lawbreaking by various means that confuse and create history spun in its favor.
The story is actually quite hokey and also vague on certain details. Yet the film manages to come across as moored to reality. There's skill shown in doing this.
As far as noir goes, it easily falls into that category.
I enjoyed this one quite a lot.