Accidental Aesop: Hercules regularly saves total strangers and gets quite famous for it, but is denied a spot on Mt. Olympus because "being famous doesn't make you a true hero." Sacrificing himself to save a single person whom he's in love with, however, is enough to seal the deal. None of Hercules' actions were purely selfless, but they were genuinely heroic, too, so the moral ends up reading something like "good deeds are negated if you reap lots of attention and money for them" with a side of "love stories count for more." The intention, of course, is that Hercules' sacrifice for Meg was more heroic because there was no ulterior motive or reward, and he was aware his life would be lost in the Pit, rather than his other battles, when he had trained and prepared and always had the chance of surviving.
Alternative Character Interpretation: We learn that Phil has trained a number of heroes and every single one of them has died horribly. We're expected to take him at his word (as does Hercules) that none of them "could go the distance", rather than consider what this says about Phil's abilities as a trainer.
Americans Hate Tingle: While the rest of the world's audiences and critics liked the movie well enough (though, of course, not to the extent of The Lion King and the earlier Renaissance films), the Greeks despised this movie, even denying the film a premiere in Greece. They didn't care much for the many, manyliberties taken with their own mythology, even if the rest of the movie was pretty decent. It's kind of similar to how a lot of American historians hated Pocahontas (even though that didn't get banned; it just got slammed with a lot of criticism) while other countries liked it well enough.
Audience-Alienating Premise: Disney's take on Greek mythology, featuring designs from the artist responsible for the animated segments of The Wall and a 1960s gospel-style soundtrack.
Thalia, the short, fat muse, is pretty much everyone's favorite. Fittingly, Thalia is the Muse of comedy - even in the original myths.
In the Disney canon as a whole, Hades has a similar thing as Frollo going on here; he only appears in one movie, and said movie is generally considered to be one of Disney's weaker works (especially compared to the rest of Renaissance), but he's still considered to be the best thing about the movie, and is many people's favorite Disney villain.
Meg is liked a lot as well for similar reasons to Hades. Many find her sarcastic sense of humor relatable and a breath of fresh air compared to the more innocent and sheltered female leads of other Disney films. She's quite prominent in fandom works like video edits and fan art, even though for years Disney never bothered marketing her or her movie. Seems to have changed in the later years, though, with Disney giving her a funky pop figurine and releasing more merch for the movie in general.
Evil Is Cool: Hades, though anyone with magical powers and the voice of James Woods would be cool. The Titans are also awesome forces of nature; the Stone and Ice Titans appeared as bosses in the Kingdom Hearts series, with the Lava and Wind Titans finally joining their brothers in Kingdom Hearts III.
Family-Unfriendly Aesop: Hercules is told that "being famous isn't the same as being a true hero". This ignores that he got famous by fighting monsters that terrorized the ancient world, and even saving Mt. Olympus from the Titans doesn't earn him godhood; he accomplishes that by performing a Heroic Sacrifice to save Meg, becoming a "true hero" based on the strength of his heart. When taken together with Phil's attitude and stories of other famous figures, the film puts forth the idea that conventional heroes (Perseus, Odysseus, Jason, etc.) performed their heroic deeds to get fame and fortune (not unlike Herc himself at first), and feats like theirs—fighting evil and saving lives—aren't "real" heroic deeds because of an inherent selfishness to reap rewards for accomplishing them.
Many, for the Greek mythology buffs in the audience. "Zero to Hero" is full of half-second allusions to Hercules' Labors, famous Greek (and Roman) art, as well as ancient Greek culture.
When the kids are stuck under a rock, they shout, "Somebody call IX-I-I!" Technically wrong (Seeing as this is Greek, not Roman) but if you know your numerals, you know they're saying "Call 9-1-1!"
When Phil says "Two words: I am retired." Hercules is confused, counting on his fingers that it's three words. But the Greek translation is "Είμαι συνταξιούχος". Two words.
When the planets are shown lining up, six are visible even though the ancient Greeks only knew about five, plus the Sun and Moon. However, Uranus is also visible with the naked eye in clear conditions despite not being noticed, so six is the correct number.
For those familiar with the Greek Myth:
Hercules telling Megara "I would never hurt you".
Herc's mentor and friend being called Philoctetes. Yes, the mythological Hercules knew a Philoctetes as well, but he was the one to light Herc's funeral pyre.
Also, Hades's design being based off of Jeffrey Katzenberg. He returned the favor with Lord Farquaad, whose design was based off Michael Eisner and was voiced by one of the original casting choices for Hades, John Lithgow.
The film's climax has Aphrodite passionately kissing Phil. Phil is voiced by Danny DeVito, and in the TV series Aphrodite would be voiced by Lisa Kudrow. Friends fans will recall a memorable episode where Danny DeVito plays a stripper who repulses Phoebe at her bachelorette party.
A few peoplenote including Grant Morrison believe this movie to be one of the best movies of Superman ever made. Just the year before Hercules came out, an Elseworld comic, Superman / Wonder Woman: Whom Gods Destroy, had Superman and the women of his life (Lois Lane and Lana Lang) all being used in power games of the Greek Gods. (Despite the title, Wonder Woman, who is generally connected to the Greek Gods in the comics, is only a red herring.)
Meg too when you think about her backstory. She made a Deal with the Devil to save the life of the man she loved, only for him to fall for another woman. And she's been forced to be a servant for Hades, and it's not a stretch to assume that her introduction scene has her in danger of being raped by Nessus.
Love to Hate: Hades. Methodic, calculating, and the epitome of deals with the devil.
This could be seen as a cartoon analogue of Clash of the Titans, which had Perseus instead (both heroes are already sons of Zeus in the myths, and both of them get Pegasus unlike the myths, and this actually has the Titans).
The part where Herc's foster parents find him up to when he talks with Zeus for the first time is much more like "Superman: The Movie/Smallville in Ancient Greece" than the myths. And Hercules temporarily gives up his superhuman abilities, as in Superman II, while his love interest temporarily dies just like what happens with Lois in the first film. All-Star Superman writer Grant Morrison even considers Hercules to be the best Superman movie.
Squick: The first time we meet Megara is while she is being sexually assaulted by the enormous centaur, Nessus. This ain't one of your happy, frolicking Fantasia centaurs. This becomes even worse to people familiar enough with Greek mythology to recognize the name Nessus. Nessus was a centaur killed by Hercules who tricked his wife into using Nessus's blood to create a poisoned tunic that caused Hercules to die a horrible, painful death.
Unintentionally Sympathetic: While the film makes it unambiguously clear that Hades is not a good person, he is, thanks to Zeus, stuck ruling the Underworld, which as he notes is "dark, gloomy, and full of dead people," while the other gods get to live on Mount Olympus. Hades is also The Friend Nobody Likes to the other gods; save for Zeus they all want nothing to do with him and the party shuts down the instant he shows up. Not to mention he seems to be much less well-regarded by mortals. No wonder Rooting for the Empire kicks in in this movie, Hades was Driven to Villainy by the other gods treating him like crap and sticking him in a terrible position in the pantheon he doesn't like or want.
Vindicated by History: When it was first released, Hercules was regarded as a box office failure and audiences had little positive to say about the film besides "It's a step forward from Pocahontas!" and it was criticized for BowdlerizingClassical Mythology - notoriously being loathed in Greece itself at the time for its supposed disrespect of Greek culture. Looking back now, many fans praise Hercules for a) having one of the most memorable and likable villains in the canon, and b) for being one of the funniest films in the canon.
What Do You Mean, It's for Kids?: Meg sacrifices herself to save Hercules by letting a huge marble column crush her. Then we see her dying, clearly in pain. Then she dies. Then you see her dead body on screen prominently for a good thirty seconds, cradled by the sobbing Herc. She sure is a lovely corpse, but she sure is dead too. Not "really just unconscious," not under a reversible Sleeping Death spell: dead. Then she's a spirit in the Well Of Souls, colorless, transparent and floating in an eerie green limbo, with the rapidly aging Herc swimming through more dead people to get to her. You know, for kids.
WTH, Casting Agency?: For both Mexican and Latin American viewers, Ricky Martin as the titular Hercules, due to his thick Puerto Rican accent. While the rest of the voice cast was voiced by Mexican voice actors, Ricky Martin's voice really sticks like a sore thumb in the cast. For a better equivalent for English speakers, try to imagine Hercules being voiced by Bob Marley, if he had been alive at the time the film was made.note This was Disney's first attempt at using famous artists to voice characters for the LA audience, so you can say they goofed up. Ricky Martin was very famous overall (though not yet internationally to English audiences) and he was signed to sing the movie's theme song for Herc. It was odd, but he did a rather good job, accent and all. It was the FIRST time it was blatant, previous Disney movies like The Jungle Book did use famous Mexican movie actors for the dub in Latin America (Baloo is voiced by comedian Tin-Tan and is fondly remembered to this day, he repeated in The Aristocats, and also voiced Little John in Robin Hood).