Icarus (and maybe even Daedalus) is the enbodiment of Jealousy (and possibly even Lust)
The whole movie is historical revisionism by Zeus himself.In some stories the end of the Age of Heroes (specifically the Trojan War) was engineered by Zeus to get rid of his illegitimate children, so it's not like this is beneath him. Zeus overthrowing the Titans in the backstory is portrayed as unambiguously good when in the original myth it brought about the end of the Golden Age. The Titans are portrayed as inhuman forces of nature instead of being more or less the same as the Olympians. Hercules is now Hera's child, which eliminates the cheating Zeus part of the story. Since that would mean Hercules is all god we need a reason for him to not be in Olympus, hence the kidnapping and the "you need to become a true hero" BS. Since it wouldn't make sense for his own mother to be his enemy, Hera gets replaced with Hades, who can't exactly leave the underworld to give his side of the story. Hades also replaces Gaia in the Titan rebellion story to cover up the complicated relationship between the Olympians and their ancestors.
Megara has more issues in her life than what's revealed in the movieIt's implied that she's had some not so great experiences with dudes who won't take no for an answer. "They think No Means Yes, and 'get lost' means 'take me I'm yours'."
Meg selling her soul made her invulnerable - AND immortal
The film was originally planned to have Typhon as the monster unleashed by Hades, and Ares would have been the Big Bad.Consider this: in the original myths, Typhon was one of the few monsters that scares Zeus, and Ares' two minions, Phobos and Daemos, were repurposed into Pain and Panic. The inner mythology buff would have loved the film even more if this is how it ended up - Typhon could be the biggest example of Nightmare Fuel in a Disney film since Ursula, and it would have been fucking metal.
The filmmakers were fans of Dungeons & Dragons.Because the Titans are totally Ogrémoch, Yan-C-Bin, Cryonax and Imix.
Zeus put Persephone in charge of the Underworld.Zeus needed someone to run the Underworld, but couldn't just let Hades go. So he asks Persephone to do it, since it's not like she's doing anything during Winter anyway.
Meg is much older than Hercules.When they first meet, Meg calls Hercules "junior", which suggests she's notably older than him. At that point, Hercules must be something like 16 or 17; the time difference between the beginning of the movie (where Hercules is a baby) and the finale is said to be 18 years, and the heroic tasks and fame-building Hercules does between the first meeting with Meg and the finale must've taken him at least a year. Meg, on the other hand, is portrayed as an adult woman right from the start. She doesn't talk or act like a teenager, and her mannerisms and voice are much more mature than Hercules'. Also, she has already been in an adult relationship with a guy, the one for whom she sold her soul to Hades. The familiar tone with which Hades and Meg talk to each other suggests that their deal has been going on for quite some time already, it's not something that happened in the recent past. Now, all this information implies Meg is about 10 years older than Hercules; she's probably in her late twenties or early thirties. There's nothing wrong with this age difference. On the contrary, it's refreshing to see a couple in a Hollywood movie who's age difference goes this way, instead of the usual older guy/younger woman pairing.
The prophecy about Hercules defeating Hades was self-fulfilling.Since Hades was trying to recruit the river centaur for what he claims is his assault on Mt. Olympus, presumably all the other monsters that Hades had at his disposal would've been used for attacking Mt. Olympus, in addition to the Titans. Hercules had little trouble killing them in one-on-one combat, but if he had to face them all at the same time at Mt. Olympus, he wouldn't have stood a chance.
Hercules' thread.When the Fates try to cut Hercules' thread of life, it suddenly turns golden and breaks the scissors, much to their dismay. Many assume it's because he saved Meg's soul before they could do it, and he became a true hero and thus returned to Godhood status. Alternatively, he didn't make it to her in time... and the universe recognized his act of knowingly and willingly putting his own life on the line for the life of another is what his ascension was caused by. So he failed to save Meg, but became a true hero and God as a result of going that far, and was essentially ALLOWED to rescue her on his own terms from there.