Ass Pull: So a man on the street that they were gambling against just so happened to have a map leading to El Dorado as the Spanish fleet were going to South America and just so happened to land right where El Dorado was? Epileptic Trees suggest divine intervention. Or that the man they conned was one of Cortez's crew, who had copies of the same map (since Cortez does wind up taking the same trail). Anthropic Principle is your friend.
Considering the man they stole the map from is seen on one of Cortez's ships briefly, it isn't as much of an Ass Pull as one might think. As to how Cortez and his entire crew got the exact same map, on the other hand…
And let's not forget the homage of the Road To movies. You know, those old black and white Bob Hope and Bing Crosby films that most children had never heard of before and are very likely to be bored by if they do see them? Perfect!
A DreamWorks animated film about Euro-American contact only a few years after Disney's Pocahontas was bound to be seen as opportunistic and derivative by potential viewers. The premise could have attracted some following in Spanish-speaking countries, but the even larger number of liberties with the source material compared to Pocahontas instead alienated viewers there.
Awesome Art: You will weep for the death of DreamWorks' traditional animation department by this film's end.
Cult Classic: The film received a mixed response from critics and audiences alike on its initial release, but has been developing a devoted fanbase over time. The reasons why are explained here.
Die for Our Ship: There used to be a site just for Chel haters. They don't give any reasons why they hate her, but this trope is the most likely reason.
Many people on fanart and fanfic sites do give this reason for hating her. That, and that she's a "slut". That the one relationship she has in the film is with Tulio exclusively and pretty enthusiastically mutual, that her mode of dress is hardly out-of-place in her home, and that Miguel flirts lightly with most of the women he stands near never cross their minds. It reach some rather hypocritical levels — Chel is no more of a hustler/con-woman than Miguel and Tulio, but it's her actions that get the scorn.
Which is outright "Hysterical In Hindsight" when you remember that they were originally written as an openly gay couple.
Others have also jokingly compared to Thor and Loki. Which means they are gods. Especially funny since Miguel directed the first movie.
Ho Yay: And how! The relationship between Tulio and Miguel is extremely close, on the level of Like an Old Married Couple. From their naked bathing together and Miguel's jealousy at Tulio and Chel to their ability to communicate ideas without speech and Miguel's use of "the face" on Tulio, along with how very comfortable they are in each other's company. Indeed, some argue that the film works best if you go through it under the assumption that the two are repressed (or even not so repressed) homosexuals.
They were originally going to be lovers. A trace of this can still be seen in the original subtitles, which have them refer to each other in romantic endearments, though whereas they were intended to be joking is unknown.
There are quite a few scenes where you see them acting rather...intimately with each other for just a second. And the fond looks that pop up more often than not are a dead give-away, too.
To be more specific: It's obvious after the ball game, where Tulio and Chel are standing very close to each other, being pretty touchy-feely. Not a second later (after the "camera angle" changes) Tulio has his hand on Miguel's chest and Chel is standing about three feet away. The animators apparently really wanted to keep the original relationship in the movie somehow.
Also, after they lose each other during "The Trail We Blaze", Tulio and Miguel put their hands where? Hips and shoulder, respectively. Very… coupley…
To be fair, bathing used to be social, such as about the time that this movie is set. It doesn't have to be that they would be so intimate with each other that they would bathe together; it could very well have been that they didn't care what it looked like, because no one really did. That's just the time they were born into - a bit less modest than nowadays. Granted, the animators could have been trying to take advantage of that fact, but still…
Chel was rumored to have been added late in production when it became apparent that they weren't going to get away with even the slightest implication of gay relationships in an animated movie. That may explain one review from Empire magazine in which the critic argues that Tulio and Miguel seem more interested in each other than Chel.