That sort of thing happened in the Sherlock Holmes stories, too. In The Adventure of the Speckled Band, Watson did it from a window.
The biggest thing Conan the Barbarian had for comic book nerds was that, unlike most comic book/pulp films of the time, the appearance and movements of the hero actually lived up to the depictions they were familiar with from the comics. Spandex heroes all looked ridiculous in live action. Lou Ferrigno led the way but was still too small to play a monster like the Hulk. But Arnold matched Conan’s unrealistic body type perfectly. And the story was on par with the not always logical, off-the-cuff tales being churned out by Marvel writers. I can’t imagine anybody watching the 1982 film for the first time in the age of CGI and the MCU to be at all impressed.
The comic books take the character, environment, portions of stories, some language, and cover art from the books to make a decent fantasy world. Something often easier to do in comic art form than in a movie. You can see from comic book covers that Arnold was the obvious choice to play a live action Conan. I liked seeing the movie, never watched it again beginning to end but some scenes were done well. I think the OP is right about the film relating an incoherent story. Common sword and sorcery themes did underlie parts of the story but for anyone unfamiliar with the background it could seem to all be incomprehensible.
When I saw it 40 yrs ago I thought it was garbage. I had enjoyed the Lancer paperbacks, but not read the comic books. I remember being annoyed that Conan seemed plodding in his actions and thoughts.
My mental image of Conan was that he had an unmatched combination of strength, speed, and animal cunning. That was what allowed him to eventually lead armies and nations. Arnold seemed to think slow and the duels were slow motion, wide-arc swings of heavy swords.
Maybe if I’d gone in without expectations I’d have disliked it less.
This and all the comments about “but have you seen what came before / concurrently???” is the answer IMHO. I watch quite a few riffed and unriffed versions of Sword and Sandals movies from say the 50’s on, and they’re all terrible. Especially the fights! And since I was a very early D&D player (I didn’t see CtB in the movies, too young, but did see it far before I could normally see R movies) it was one of the first movies that felt like it was for -me-. Combining the comparatively ‘real’ violence with what is still one of my top 10 soundtracks of all times made it a huger winner for me.
And while in terms of coherent story, I’d agree that Beastmaster makes a bit more sense, all the other elements (the cute ferrets, the kid (Tal), and the off tone jumping between the more family scenes and quite a few of absolute horror (the eagle people and the parasite) never made it work for me.
I did end up reading quite a bit of classic Howard a few years later, which thankfully insulated me from the “But his hair / origin isn’t canon!” arguments earlier on, and these days I have a complete edition of de-edited Howard stories, and enjoy them on their own merits (although almost more as Mythos stories than fantasy though).
But back to the OP, anyone seeing this after say, Lord of the Rings is going to say “Whut?” at the fondness held for this one.
For that matter, there’s Jason Mamoa’s 2011 CtB - modern effects, a powerful bodied main lead, much more appropriate appearance, and a story that borrows from Howard’s mythos although in a very muddled manner and it feels utterly flat. Boring. So again, the original is absolutely being seen as by what came before and being a new standard. Other than a few quotable bits and a timelessly awesome soundtrack, the movie ITSELF isn’t all that great going by it’s on-screen material.
I read some of both the comic books and the non-illustrated stories before the movie. I still think it is one of the better sword+sandals movies out there, and probably the best of its time. It has an incoherent story? I don’t really remember any over arching plot in either the Conan books or comic books. So, the story being a few loosely attached vignettes seems to fit Conan fine.
And yeah, that soundtrack is one of the best.
But then again, it’s no Korgoth of Barbaria. Too bad it was too expensive to make more than the pilot. Supposedly they’re making a live action version now.
My kids, now 16 and 13, have never scoffed at the special effects of older films (the cutoff being the late 1970’s, I think). This is because much of the current CGI is just so obviously computer-generated, and really no better than the refreshingly non-computer generated old school effects. Not that I’d say my kids were impressed with Conan the Barbarian that way.
I was six or seven when I saw Arnold’s Conan for the first time, because my parents didn’t really love me and didn’t track what I watched, and when I first read Conan stories a decade later I realized he was a lot different there than he was in the movie. Conan was well built, but not a hulking brute, who moved like a panther, exhibited a great deal of intelligence, was a polyglot, and literate in more than one language including a few dead ones. Had I read Howard’s stories first, I might have also been disappointed with the movie.
I did enjoy Marvel’s The Savage Sword of Conan which because of its format didn’t have to adhere to the Comics Code Authority in force at the time. I wasn’t able to purchase them myself, but my friend’s older brother bought them so I’d read them when visiting.
Humor is a important part of the movie. Mako and Arnold have some funny back and forth comments. The scene with Mako wearing the over size armor is hilarious.
Surfer Gerry Lopez is also good playing off Arnold.
Sandahl Bergman was a professional dancer that worked in several projects with Bob Fosse. She brought that skilled movement to her role in Conan. I really liked the scene where she goes down a rope to steal the eye.
Arnold is pretty wooden and inexperienced. But the other actors play off his muscle bound character quite well.
This is a big part of the deal with the OP feeling “there is no story” – it is basically a sequence of “the scriptwriters’ top favorite scenes from a reassembled Conan timeline, + minimal connecting backstory filler”. There was no obvious real grand epic arc in the original.
As mentioned, the casting choice was more for the sake of the fans of the later paperback edition covers and of the comics. In the actual Howard stories Conan was a “barbarian” in the classic sense of an outsider to the main civilization, not in the sense of being some sort of brute.
A putative “Conan film franchise” was to a great degree stymied by Arnold’s own climb into legit action-hero stardom, and the awareness of backers that nobody else at the time could really carry it (possibly in the face of the overproliferation of other “barbarian” movies that have been quoted earlier in the thread resulting in any momentum for the idiom being spent).
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Re: 80s sword & fantasy movies, at the time I said that what we really needed was to put the Excalibur score behind Ladyhawke. That would have been a winner. I suppose they overshot the budget and had to cut the scoring in favor of “ok, my cousin has a top-end Casio and a mixing board” 
I didn’t notice the user name at first and my mind went to a ferret named Madam Pepperwinkle.
Nope, it was a conscious decision according to Wikipedia:
Richard Donner stated that he was listening to The Alan Parsons Project(on which Powell collaborated) while scouting for locations, and became unable to separate his visual ideas from the music. Powell combined traditional orchestral music and Gregorian chants with contemporary progressive rock-infused material. At the time, it was part of a trend among 1980s fantasy films of abandoning the lush orchestral scores of composers such as John Williams, James Horner, and Jerry Goldsmith in favor of a modern pop/rock sound.[10]
Same approach was taken later in « A Knight’s Tale » with Heath Ledger.
The best scene in that movie for me was in the opening where the wall of bloody faces comes alive.
I prefer Lamentations.
Read Robert E. Howard’s stories. Ideally not the later additions and emendations by other authors. They’ve republished the only-by-Howard stuff in the past twenty years.
I was a huge Conan fan, having read not only the Lancer paperbacks, but also all the Marvel comics (including Savage Tales). I also sought out the other Howard fiction published by not only Lancer, but Dell and Time Lost and other places.
And I hated the Conan movies.
There was virtually no Robert E. Howard in the films. Give me The Tower of the Elephant or Red Nails or The FRost Giant’s Daughter or Hour of the Dragon. Don’t make up what you think should be the Conan story, because you won’t get it right.
The best Conan movie to come out in 1982 was Albert Pyun’s Sword and the Sorcerer, because he stole the best scenes – The long-dead wizard being resurrected from his sarcophagus, The Barbarian hero crucified on a tree, etc. – from Howard’s Conan stories. This was something none of the movies has done. Of course, his movie had a lot of awful stuff in it (like a triple-bladed jet-propelled sword), but at least we got to see some of Howard’s imagined scenes put up on the screen
Go to 0:37 here:
The weakest part of the film is during Conan’s slavery. The grinding wheel really ground the movie pace to a halt. 
His early arena fights with little training and discovering women didn’t quite work for me. I understand the exposition is necessary. I’d guess it came from the comic books. But the story could have been told better.
Talking about what worked best for me is of course the opening, with the raiding of the village and the loss of his people. While utterly non-canonical, it was absorbing, and the music made the whole sequence sing.
Which is followed, as Aceplace57 noted, by a sequence of dull drudgery.
But my probable favorite bit is highly unusual. It’s the bit where after the successful smash and grab the group parties so hard they’ll glassy eyed and passing out. One of the things about Howard’s Conan stories is that Conan, while smart, skilled and lucky is very prone to screwing up things for himself in the good times. Stealing the wrong thing, punching the wrong man, or sleeping with the wrong man’s woman. He’s gone from barbarian to thief to warrior to slave, often repeatedly.
So seeing that tiny bit where the ur-character leaks through is always fun for me.
Although if you asked which line gets quoted MOST by my friends, it’s “Dinner for wolves”. We use it anytime someone talks up a good game, or a good plan, but the reality is different - Dinner for wolves.
What, no love for The Barbarians? (IMDB link)
Not really, though. A Knights Tale used modern pop music as deliberate anachronism. It’s supposed to be jarring and funny when the audience at a 12th century jousting tournament start singing “We Will Rock You.” The soundtrack to Ladyhawke, in contrast, was meant to complement the story and visuals. It’s not meant to be anachronistic: when that Alan Parsons Project music kicks in, you’re supposed to react to it like when the John Williams score kicks in in a Star Wars movie, not snicker at the idea of someone in pastel spandex and mirror shades hanging out behind the stables with their Moog.