An integral part of Disney's Renaissance, Hercules (1997) did not perform as well commercially as its predecessors (or successors.) Nevertheless, it is regarded as one of the finest accomplishments in the animated film genre, mainly due to its easy plot, devastating sass, zany side-characters, and, of course, the magnificent Hades. In fact, Hercules is officially in line to receive a live-action adaptation, with the Russo brothers in producing roles.
What many people are unaware of is the fact that the film spawned a related TV show known as Disney's Hercules: The Animated Series, which covers a lot more ground and has an enormous cast, especially in terms of the Olympian Gods and other assorted deities. Since it's a cartoon meant for children, the creators chose to redesign these mythological icons to suit the demographic. How different are these beings from their real versions, though?
Hades
The real Hades is not at all the sassy, evil monster shown in the film; to the contrary, he is a true embodiment of death, given his position as the absolute ruler of the underworld; he never takes sides and always maintains an unbiased demeanor.
In stark opposition, the Hercules villain hates his job and regularly tries to conquer Olympus from his big brother (because envy). These trickster-like tendencies play extremely well in fiction, but they distance Hades' personality from the character that he is based on.
Gaia
In the show, Gaia spends eternity mostly sleeping, only waking up if someone annoys her too much. For instance, when Adonis forces her awake for one of his quests, she furiously proclaims that he will be dead before sunset for having the audacity to disturb her slumber.
Luckily, Hercules aids him in obtaining a bunch of golden apples to placate the angry goddess. The mythological character, like this one, also symbolizes the world, but she is depicted in a far more maternal way. There is a reason she is called Mother Earth.
Hera
First of all, Hera is not supposed to be Hercules' mother (who is, in fact, a human woman named Alcmene.) That aside, the film variant is radiant, her shimmering beauty only eclipsed by her gentle nature and tender compassion.
On the other hand, the deity is best known for her extreme jealousy, almost all of it directed against her husband's innumerable partners and the resulting children thereof. She even curses the nymph Echo to forget how to use language, but instead be stuck repeating the words of the person speaking to her (which is how the word was derived.)
Zeus
The cheerful dad of Hercules doesn't quite resemble his actual role as the chief of the Greek gods, a decidedly malevolent entity who rapes and murders with abandon, sires a host of offspring, not to mention randomly cursing and intimidating mortals who can't really fight back (unless they want to be electrocuted to a crisp.)
In the film, Zeus is a lot more jovial, if a little headstrong, but generally exudes a fatherly warmth and wants the best for the world as well as his son.
Hecate
The goddess Hecate represents magic, medicine, light, and a lot more different things, none of which have overtly negative connotations. In later theological writings, her role was expanded further, being mysteriously referred to as the "Cosmic Soul" and the "Angel Mother."
TV Hecate is like Hades, except that her aim is to wrest control over the latter's dominion, a fact that he explicitly does not enjoy. It's almost like the showrunners were running out of new ideas for ancient Greek villainy.
Poseidon
Poseidon is one of the most powerful gods in the Olympic pantheon, taking credit for everything to do with water (and horses, but that's not relevant here.) As the patron god of sailors, he reigns over the seas and oceans and blesses all those who come to him with their prayers.
In comparison, the animated Poseidon is shown to be a spineless cretin who easily falls for Hades's scams, such as helping him shift the Styx from the underworld to Greece, which would change the borders between his and Zeus's sterritory.
Athena
In the series, Athena is a powerful goddess: the personification of intelligence and wisdom. This makes her very similar to the mythical version, except she isn't shown to be as badass as she's meant to be.
For instance, it's usually Hercules who saves the day whenever Athens is at risk of destruction at the hands of Ares, which just doesn't make sense given that Athena is also supposed to epitomize the art of war (sculptures and paintings often portray her with martial gear, such as lances and helmets.)
Hermes
Hermes in both cases share identical symbols of status — being the "Herald of the Gods", in addition to nourishing the likes of traders, robbers, and travelers.
They can each travel at great speed, aided by a winged helmet and identical sandals (and also carry a caduceus staff with them.) The differences are minimal but contrasting, the chief of which is appearance. The Disney character is a cheeky blue imp, while the heavenly being is usually shown as a teenage boy or young man.
Apollo
Apollo is one of the more relaxed gods, representing the sun for the most part (but also dabbling in sports, the arts, medicine, prophecies, and so on.) He is usually called upon by worshipers in exchange for boons, usually, because he is the most likely one of all to accede to his devotees' wishes.
In the Hercules show, Apollo is quite similar in terms of temperament: tender but firm when necessary, like when he accuses Zeus of being a terrible leader because he mistakenly suspects that the king of the gods loses his chariot (Hercules being the perpetrator here).
Artemis
Artemis might well be the mirror image of her mythological source — the lunar goddess overseeing the fields of hunting, ranging, wild animals, and nature in general. In line with historical expectations, she happens to be the child of Leto and Zeus, simultaneously being Apollo's twin sister.
Most interestingly, the actual Artemis, just like her animated counterpart, has a strong affinity for deer, the animal with which she shares a deep and sacred bond.