Factual error: Hernando Cortes is featured as the main background villain. Only thing about his appearance: according to the history books, he never actually ventured into South America to do any conquests; his actions were limited to Cuba, Mexico and California.
Continuity mistake: In one scene the ball players are kneeling in the background while Miguel is protesting Tzekel-Kan's intention on sacrificing them. In this shot, one of them has blue feathers in their hair and one has red feathers. A few seconds later, they lift Miguel on their shoulders, and none of them have any feathers in their hair.
Continuity mistake: At the end, Miguel notices that Tulio's sail is stuck, so he rides his horse down a huge staircase and jumps onboard in order to save him. In the shot of him jumping on the horse for the first time, the natives are seen in the background on the same level, holding onto their ropes. Then Miguel starts riding down the staircase, and suddenly they are all the way at the bottom, by the river.
Factual error: The real El Dorado (Spanish for "the gilded one") civilization was in South America. Specifically, El Dorado is a legend coming from the Muisca people of Colombia. The art scheme of the film is Mayan, a Central American civilization, as are the names of the Indian characters. The ball game, too, although not restricted to the Mayas, is, culturally speaking, Central American (and more specifically, and technically, Meso-American). In addition, the Mayan architectural elements found in the movie are typical of the Mayan culture of the Classic Period (c. 250-900 C.E.), roughly 600 years before the arrival of the Spaniards.
Continuity mistake: After Tulio tells the sailors that they have nothing to bet with one of them replies "Oh yeah, I got this" and shows them the map. When he does this, the face of the weeping woman on the map faces to the left, however later in the film when the two men use the map to identify where they are, the woman's face faces forward.
Continuity mistake: When Miguel and Tulio see the fountain shaped as a weeping woman, there are plenty of trees nearby and rocks are visible in the middle of the river. Later in the film, when Tzekel Kan surfaces at this area after falling into the whirlpool, the nearby trees are totally different, and the rocks in the river have vanished.
Continuity mistake: When Miguel and Tulio fall off the cliff at the end of "The Trail We Blaze" and land next to the tall rock carving, Miguel is briefly knocked unconscious when he hits the ground. When he is first shown on the ground, he is lying with his head a couple of feet away from the rock. A few seconds later when Tulio kneels down to wake him up, he is lying with his back right up against the rock.