I think Peter Bradshaw's glowing review in The Guardian might have been a bit generous ('pathologically brilliant... the film radiates a kind of electric, shamanic craziness'). I think he misunderstands Gibson's right-wing narrative dynamic.
Those naked corpses. What was Gibson thinking? Did he realise what he was doing? Did he realise what images and ideas he was invoking? Well, the director is certainly inviting us to sympathise with the captured and enslaved wretches, so it could be that this is the nearest he will ever come to some form of cinematically constituted apology. And how about the link between this bizarre human sacrifice and Christianity itself? Does Gibson mean us to see it? Does he see it himself?
I think this film is not insanely off-centre, I think it's tightly in line with right wing white christian attitudes to colonialism (and there has been plenty of that in England of course for hundreds of years). The story goes that the European invaders rescued the native peoples of other continents from a hell of paganism, starvation and oppression. Thus the genocide of non-Europeans is re-imagined as the rescue of those people from genocide. It is a made-up story which serves a political agenda.
Gibson's mad creative gesture is to take the story seriously. Just like he did with Passion of the Christ. He took a story that people mouthed bloodlessly, and rendered it as literal blood and guts on the screen. How do you like your blue eyed boy now?