Conan the Barbarian (1982) has no right to be as good as it is. On paper, it's a dumb sword and sorcery flick with a body builder who could barely speak English in the lead. But everyone involved does an incredible job, from the acting to the directing, to the score. It's a crime that Destroyer trashed up the formula, and we never got Conan the King.
I watched it expecting the same campy tropes from other fantasy/sci-fi movies of the era and what I got was a movie deeper than it lets on. That score too, amazing.
It defined the genre in a lot of ways. There's a reason so many 80s flicks tried to emulate it on the cheap. It's the same as "Star Wars" to so many "Battle Beyond the Stars" movies that followed.