Warner Bros. refused to do a director's commentary for the DVD release, so Darren Aronofsky recorded one in his living room and released it on his website.
Instead of using CGI, Darren Aronofsky chose to do the visual effects for the film by using micro-photography of chemical reactions on tiny petri dishes. He has said that CGI would take away from the timelessness of the film, and that he wants the film to stand the test of time.
Of the seventy extras cast as Mayan warriors, twenty were actual Mayans flown in from Guatemala. Fernando Hernandez, who played the Lord of Xibalba, was the only one who could speak English. Before shooting at the Mayan pyramid, the Mayan actors blessed the set.
Darren Aronofsky originally planned a major battle between the Mayans and the Conquistadors, but budget cuts and the release of grand epic battle films (Peter Jackson's "Lord of the Ring" films, Troy (2004) and King Arthur (2004)) made him change his mind and rewrite be mainly between Tomas Verde and the Mayans. Aronfsky realized that this worked out better: one man against the army represented a man defying odds.