Classical myths never really had only one version. Each myth had multitude of variants. Each of those myths was told in hundreds of ways. It is just that only few versions are usually preserved. If we take myth of Lycaon for example. There are multiple versions of what happened. In one version Lycaon was transformed into wolf as a punishment for killing and then serving his son on a platter to gods. In other, it was his fifty sons being transformed. In one other it was the sons that killed their brother, and were punished by gods by being transformed into wolves.
You might see where I am going with this. Even with all those different versions of one myth, there are still the same people involved in a myth. What changes are happenings in the myth, maybe sometimes attitude of some character in the myth. But it never tries to be something that is not. It always tries to stay true to the source. This is probably the reason why people respect Camus's Myth of Sysiphus as a modern iteration of the classical myth. Yes, I agree, Myth of Sysiphus is by itself a great work, but it is also a work that respects its roots.
The classical myths are highly iterative. Which, for the purposes of film-making industry should be a gift from heaven. Instead they always want to make it bigger, better, faster. And at the end, what we get is instead an abomination that would turn Medusa to stone. What is really sad, is that Clash of the Titans from 2010 is a remake of the Clash of the Titans from 1981. What the hell?
They decide to do a remake of the first film that botched it completely, and want to stay true to the source, the first film that is, instead of just taking the name and then iterate on the original myth. For which I can attest it is much better, a lot juicier, and highly more entertaining. Even with a pedagogical note in it. But God forbid if films ever tried to have a moral note at the end. Next time they decide to butcher a good myth, I would like them to do it by staying true to the source.
What irritates me about the movie are two things. There are more, but those two are so grave that would make Oedipus stab a pole into his eyes, not the pins if he ever saw it. I talk about the infamous kraken, and the duality of gods.
Kraken, is not a beast from classical mythology. Kraken belongs to the Norse mythology. These two, never clashed, never met, never heard of each other. They were not far apart only in space, but in time as well. So why, oh why is there a Kraken serving Hades, the god of Underworld? Why is sea creature under a command of Hades, if there is perfectly good sea god, called Poseidon. Poseidon actually wields a trident. In original myth, Perseus dealt with a sea monster. Indeed it is not specified what this monster is, but it is sure not a kraken. If the ancient depictions are to be believed it was a giant sea serpent.
Now to this good gods, bad gods. Gods in Greco-Roman religion and mythology are human in nature. They are so flawed, and so full of mistakes and sins it could be hard to believe. Hades for most part is one of better ones when it comes down to behaviour. He rules the Underworld. No, not hell. Underworld. This is where all the souls go after they die according to classical mythology. No he is not some devil waiting with pitchforks and a lot of flames around him. Underworld is not hell. Tartarus is hell. And even there are no flames. Tartarus is an abyss.
If there needed to be a bad guy in the whole movie, it could simply be Poseidon. It is he to whom King Cepheus must sacrifice his daughter Andromeda to appease the god's ire. It was the Poseidon who sent the sea monster every day to feast on the flesh of mortals.
In all the classical mythology there is not a god without flaw. Even the most pure and innocent did something wrong. Even Athena, the goddess of wisdom and tactical warfare. Even Apollo, the god of light and wisdom. Even Zeus. Athena helped cause the Trojan war. Apollo raped a woman, and tried to cover his deed. Let us not lose time on Zeus. The number of times he cheated on Hera, the number of women he took, his mood toward those that defied him, He is full of flaws. Even if he is a supreme god he is far from perfect. One could say, he is most human of them all.
Let us get back to Hades for now. Hades in original myth helps Perseus in his hunt for Medusa. By one version Hades gives him a Cap of Invisibility, that hides Perseus from the look of Medusa. Athena gives him the shield that can reflect Medusa's glare back at her. And Zeus gave him an Adamantite sword with which to slay the only mortal of the three Gorgons.
Now let us imagine they stayed true to the original and only iterated upon it. The theme that mortals do not need gods, could still be preserved. The theme that mortals prevail in the end would still be there. So if I wish for anything, it is a tiniest bit of respect be shown to the original myths. And not just twisting them into something they are not. I would rather not have a film about classical myth, than have a film that has nothing in common with the myth in question.
Adapting a classical myth into a film really should not be hard. Those are stories known to all. And in their basic form they can be placed in whatever time, whichever place. They will still function. Intergalactic Trojan war, King Oedipus in post-modernism, steampunk Odysseus. You see where I am going with this? The story will always work.