(at around 1h 8 mins) Just after Akiro reads the legend on the wall of the crypt regarding the woman-child with a certain mark, we are treated to a view of the mark that makes Jehnna so special on the swell of her left breast (a pink star shaped mark). However, earlier in the movie (at around 45 mins), when Jehnna first awakens in the castle of Toth-Amon as well as the scene a few minutes after this when she lifts the jewel/key from its place, this same area of her chest is perfectly visible but the mark is not there.
(at around 17 mins) Shortly before Akiro is rescued from the cannibals and joins the party there is a scene where Akiro can be seen on the last horse riding through the forest despite not having joined the party yet.
(at around 26 mins) When Zula is fighting Bombaata, she leaps from the saddle and throws herself on him, knocking his head-circlet off from the impact of collision. In the very next shot, Bombaata's circlet is back on his head as he struggles with Zula.
(at around 49 mins) During the opening sequences between the sword fight with Togra and Conan. You can see Togra wearing a long cape in the long shot. When they do a closeup of Togra drawing his sword, he's not wearing the cape anymore, but when they charge at each other on horseback Togra is wearing his cape again. When the swords clash in the closeup, the cape is once again missing for the rest of the fight.
(at around 1h 6 mins) Malak locks the stone gate by pushing the lever to the left, but when the rest of the party enters the room, the lever is to the right (unlocked) again.
(at around 32 mins) When the heroes are 'rowing' toward the castle, Conan is 'rowing' with the rudder, which is clearly not designed for this purpose, and the oars are nowhere in sight. It could be said that rowing with this type of rudder is possible, using a vertical rhythm that ran in parallel with the skiff (boat), however Conan was rowing in perpendicular - from left to right.
(at around 1h 20 mins) During the escape through the tunnel, Bombaata caves in the tunnel. Conan then digs through the rock pile and crawls over the stones; they bend like foam.
Set in a primitive era, thousands of years before the rise of the known ancient civilizations, the women have shaved legs and armpits.
(at around 50 mins) During Conan's first fight with the barbarian that steals the princess off the horse, he and Conan engage in a horseback sword fight. Conan holds up his sword waiting for the enemy to strike his "block" and eyes the enemy's sword as the target rather than the enemy himself. Near the end of the horseback segment, Conan actually hits his opponent's hilt and fingers rather than the blade (a filming mistake), but the fight continues as though it had been blocked by the enemy.
(at around 41 mins) During his battle with Man Ape, the blue make-up used on the monster can be seen rubbing off on Conan's body in various scenes for short periods.
(at around 1 min) Telegraph poles visible behind Conan's group as they gallop across the windswept plains of Yore, in the opening scene.
(at around 5 mins) When Taramis' guards are trying to capture Conan, Conan hits one of the guards' rope nets with his sword, yet it makes the noise of metal against metal.
(at around 5 mins) Just after Conan and Malak are surrounded by Taramis' guards at the start of the film, Malak asks, "Why are they trying to kill us?" As Conan answers, the same line of dialogue can be faintly heard playing again.
(at around 43 mins) When Conan is fighting Man Ape and discovers that breaking the glass panes hurts him, it cuts to a shot of his friends behind one of the panes, and Malak says, "That's exactly what I would have done, exactly." His lips don't match the words at all.
When Conan and the entourage enter the village where Zula is being held captive, Bombaata says "Thieves should be hanged." It is obviously overdubbed and it looks like he is quietly speaking the line a second time.
(at around 5 mins) During the first battle, when Conan hits the second horseman with his sword, as the man falls from his horse there is a shadow of the cameraman on the ground.
(at around 1h 24 mins) When Malak falls from the waterfall towards the end of the movie, Conan has to catch him and save him. There is a harness attached to Malak's back as he's falling.
(at around 47 mins) During the escape from Thoth-Amon's collapsing tower, the silhouette of a crew member or a mechanism is visible inside one of the rocks (the largest rock just left of center at the top of the screen.) Just before the scene cuts to the next one, a shadow of a crew member is visible at the extreme left of the screen.
(at around 3 mins) In the first shot of Conan kneeling on the ground with his sword, a crew member can be seen walking out of the shot on the far left side of the screen.