Faraer said:
Well, Conan the Barbarian took various images and elements from various Conan (and Kull!) stories and stirred them into a new narrative: it certainly is a hotchpotch, but I'm not saying that's inherently bad. But Conan is intelligent and articulate, melancholic and haunted by his memories of Cimmeria, fundamentally Celtic (like many of Howard's other leads); and the Milius-Schwarzenegger character isn't (but he does pray to Crom and lives as a slave for years which Conan wouldn't have done). Those are the biggest differences for me.
Yes, there are differences between the two portrayals of Conan, and there are also similarites. Howard's Conan is a raw, primal savage, almost an elemental force of nature. He posesses a keen and intelligent mind and the spirit of the untamed wilderness. Combining the inhuman strength, speed, toughness, and intelligence, Conan is a larger-than-life warrior king taken straight out of myth and legend. (Although I wouldn't use melancholic or "haunted by his memories of Cimmeria" as ways to describe Conan)
Milius, who is a long admirer of Kurosawa's samurai films, took a few artistic liberties with the character, which included the likening of Conan's development to a sword being forged from the development (because to a samurai, the sword was the soul of the warrior). Milius' Conan begins as a raw chunk of iron, strong but unfocused. Through his expiriences as a gladiator and education as a warrior, the forging of the sword begins and continues throughout the movie. Milius' Conan is a barbarian warrior with a samurai's spirit, who has learned focus and discipline, who has combined a powerful physique with education and cunning.
Of course, there are similarities between the two adaptations of Conan as well. Both are womanizers, both have a love for drink and celebration, and neither version lets a slight pass. Neither are big talkers, preferring instead to speak through their actions.
Milius read into Howard his own Nietzschean (some would say crypto-fascist) philosophy and made a John Milius film. There's enough of a linking thread that it's not an altogether absurd switch; but there's so much more to Howard's underlying themes that the film just knows nothing about.
Conan the Barbarian opens with the Nietzschean phrase "That which does not kill me only makes me stronger." This is important because it basically sets the tone for the entire movie. After his village is raided as a child, Conan is forced to push a giant grinding stone called the Wheel of Pain for several years. He manages to survive the harsh conditions of his slavery while the other children fall over the years (until eventually Conan is the only one left pushing the wheel), and by the time he reaches adulthood Conan has become a physical powerhouse. The Wheel of Pain did not kill him, it made him stronger. Conan's next test is in the gladiatorial combat arena, where he again persists and survives the challenges presented to him. He survives the fighting pit, and emerges a seasoned warrior and a master of weapons. This trend continues throughout the film, with Conan facing challenges that fail to kill him and instead leave him stronger, wiser, and even more dangerous than he was before.
When directing Conan the Barbarian, John Milius set out to create his own version of Nietzche's
übermensch, the self-actualizing, self-overcoming overman. Although Milius' Hyborean-age psudo-samurai may be different than Howard's Conan, both are fascinating and incredible characters in their own right, which is why I'm not upset over the fact that Milius' movie isn't a word-for-word retelling of one of Howard's stories.
Howard's Conan stories traditionally revolve around civilization versus savagery, although that theme is only present in a few stories, such as
Beyond the Black River. Milius' film is full of symbolism and subtext as well, and can be explained by this in-depth and incredibly well-researched article:
A Critical Appreciation of Conan the Barbarian, written by David C. Smith, the author of nearly twenty fantasy and horror novels, as well as several short stories.