These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
YMMV: El Dorado
Ear Worm: That opening song is surprisingly catchy:
So ride, boldly ride
To the end of the rainbow,
Ride, boldly ride
Til you find El Doradoooo...
Ensemble Darkhorse: Nelse McLeod is a surprisingly likeable character and in some ways a more honorable fighter than Cole Thornton.
Recycled Script: Many situations and plot elements are very similar to those of the previous Hawks/Brackett/Wayne western, Rio Bravo, and to those of the next and last one, Rio Lobo. Some elements are inverted, e.g. instead of the hyper-competent Young Gun of Rio Bravo you had a youngster who is useless with firearms. The scene in which Thornton pushes one of McLeod's mooks through a door to be shot by his own men echoes a similar one from the first Hawks/Brackett collaboration, The Big Sleep. There also had been a scene similar to the one where Mississippi throws himself in front to the bad guys' horses that was cut from the final version of Rio Bravo, so to do it here, Howard Hawks bought the rights back from Warner.
Special Effect Failure: When Mississippi throws himself under the bad guys' horse, there is a very obvious cut where James Caan is replaced by a dummy in mid-dive. Hilariously, the dummy gets trodden on at least once, immediately before Mississippi's explanation to Cole, "A horse will never step on a man!"