A fairy-tale for adults, indeed.This film is alternately brutal and charming, horrifically violent and innocent, darkly gritty and... well, bright is the only thing the film isn't. One of the few things missing from this picture, imho, was splendor. If the premise of a movie is going to be the existence an alternate fantasy world filled with imaginary creatures and dangerous adventures, you would think that there would be a least a few grand, breathtaking, gorgeous scenes in that world... but no. Here we see the entrance, and a rather cold, empty court of the King of the Underworld at the very end. But, as I said, one of the few things missing.
Everything else - acting, sets, costumes, pacing, etc. - help make the duality at the heart of the film work very effectively. We can see the parallels (well, at times they are beaten into our heads) between the depressing and harsh Spanish Civil War era and Ofelia's secret kingdom. Whether the symbolic links are the result of Ofelia's unconscious processing and delusional recycling or not - that actually makes no difference to our enjoyment of these two intertwined stories. It's well done and smooth, and the Spanish dialogue (with intact Castellano ceceo) is soft on the ear, very captivating.
Questions: how immoral or moral a character is the Captain? After all, his does have great concern for his infant son, and of course his loyalty to his military duty.... On the other hand, he points out himself he is guilty of excessive pride. Is his concern for his son simply a concern for his bloodline and name to be continued? If the rebels had told him their final words earlier ("he [the son] won't even know your name"), would he have handed over the baby? Is his commitment to military duties, including the extraction of intelligence through torture, inexcusable?
Why, in the Hombre Pallido's chamber, did Pan's [Faun, actually] fairies indicate the wrong door for Ofelia to unlock? And was the fact that she corrected herself suppose to prove her royal heritage? (The 'proof of divine heritage' is an element which recurs throughout world myths.)
And why these choices for translations? Why not Faun's Labyrinth? And Ophelia? And the Pallid Man? By saying Pan, they draw associations with Greek mythology, but then seem to avoid Shakespearean analogies by using Ofelia instead of Ophelia. Boy, what if she had been Persephone instead? And was there some detectable influence from Nausicaa here as well - both from the Odyssey and Miyazaki's manga, which Del Toro is clearly familiar with?
This movie also reminds me of one of my recent favorites, 新造人間キャッシャーン [Shinzo Ningen Casshern], which is another fantastic, allegorical, and ultimately severely anti-war movie. Another example of the great efficacy of using the fantastic, weird, or imaginary (sci-fi, fairy tales, fantasy, horror, etc.) as a mirror through which we see the true nature of the 'real world.' *

