The first thing to say about this film is that the 139 minutes running time felt like about 60 minutes. It kept you fully engaged every second.
The quote at the start about corrupt civilisations dying first from within proved to be a red herring. This was not about the Mayans going through their decadent final phase. Although the scenes of superstition and sacrifice seemed to point in the that direction., this was not followed through. It was essentially a ripping yarn with an extended chase sequence.
It's very easy on the eye. The cinematography was sublime – tasty visions of the Mexican wilderness abounded. Some of the set pieces were astounding – especially the sacrificial altar scene atop the stairway to heaven, with its attendant grotesques ; and the spectacular arrival of the Spaniards; and the field of the dead etc.
The non-professional cast were excellent although all the acting required was within the melodramatic range. The costumes and make up were spectacular – especially the body carvings and piercings.
There were of course lacunae. The wife n the hole (literally and metaphorically) bit became increasingly risible, culminating in the underwater birth.
But this is Mel Gibson not Bertolucci. His track record suggests good action movies (Braveheart, Lethal Weapon, Mad Max) and this is what we got.