As a big fan of mythology and the Iliad, I'm pretty surprised by how nitpicky people are being on the details. Having taken a "Mythology in Film" course, I can safely state the following:
1) It's not supposed to be "The Iliad," it's "Helen of Troy." 2) It's a film. Made 3,000 years later. Targeted at an entirely different audience. 3) Greek mythology tends to be greatly inconsistent anyway, depending on your source. 4) Patroklus is never mentioned to justify Achilles's rage against Hector. So what? If Achilles hadn't withdrawn from war, he would've killed Hector anyways. And having him withdrawing and re-entering into the war would only have distracted from the main story (Helen) without really adding anything.
There's a difference between myths and literature. One can stray from the literature of a story while staying true to the mythology of it. The Iliad itself was constantly being reinvented by generations of oral poets who changed the story every time they performed it. Back in ancient times, a person who merely recited the story verbatim would be considered an inferior, because he'd merely be a copycat rather than a storyteller.
When it comes to the spirit and tradition, "Helen" shines. For instance, in the Iliad, Achilles compares Agamemnon taking Brisius to Paris taking Helen. In the film, the comparison is made literal. Brilliant. Then you have themes and scenes taken from the Orestia. Three or four different ideas are brought together in the span of one.
"Helen" may be a bit loose with the details, but it shows a good understanding why those details took place, and stays true to capturing their motivations. Just because they don't follow the material exactly doesn't mean they don't know it really, really well. The same is true for a lot of other film productions, from "Desire Under the Elms" to "O Brother Where Art Thou" to "Medea" and even "Clash of the Titans."
All and all, a good flick, I was pleasantly surprised. My only real complaints was the casting of Achilles (I assume they were combining his character with Ajax/Diomedes) and the fact that Hector never gets to actually beat anyone in combat (That was disappointing, to say the least).
