Errors in geography: A small American flag is visible on the "Russian" helicopter that Rambo steals.
Continuity: While kick-boxing in Thailand, Rambo offers his right hand to his opponent who fell on ground but when he comes up he's holding Rambo's left hand.
Factual errors: When the troopers lead by the Colonel stops no sound is heard, all of a sudden you hear the sound of a helicopters rotor fade in, a few seconds later the helicopter appears and starts to slaughter the men. The night was clear and it was in a desert, those are ideal conditions for sound to travel (even a whisper will be heard over a good distance) and seeing how a helicopter creates a very high sound from both the motor and the rotorblades they would have heard the helicopter several minutes in advance.
Factual errors: Almost every time the Russian gunship helicopter attacks and is filmed from the front, there are muzzle flashes coming out of the rocket pods, but no rockets are being fired. Even if rockets were being fired, there would still be no muzzle flashes.
Factual errors: Zaysen’s rank is a Colonel, but he wears a kind of mixture between Senior Lieutenant (3 small stars and 1 stripe) and Colonel (3 big stars and 2 stripes - he has 3 small stars and 2 stripes). His army coat is also obsolete.
Factual errors: Soviet soldiers can be seen wearing different kind of hats (winter and summer ones) at the same time, which can't happen in the real Army.
Factual errors: In all the gunship scenes, the door gunner is obviously firing a Belgian made MAG58 machine gun, a NATO standard weapon. It is not found on any Soviet helo.
Continuity: In First Blood, Rambo has tons of scars on his back. In this movie, in the scene right before Rambo goes into the warehouse for the stick fight, there is a shot of his back and you can see that the scars are gone.
Revealing mistakes: The last time Troutman saw Rambo was at the end of Rambo: First Blood Part II (1985) in 1985. However, the photograph he has of Rambo that he is carrying around showing people was obviously taken in 1988, as you can tell the level of aging on his face and the length/style of his hair more closely resembles his image from Rambo III (1988), and not that from Part II.
Continuity: During the stick fight scene, Rambo throws a kick at his opponent, misses, and his foot gets stuck in the wall. It cuts to another shot where both of Rambo's feet are on the ground, and then it cuts back and his foot is stuck in the wall again.
Errors made by characters (possibly deliberate errors by the filmmakers): When Rambo is struggling to remove the grate in the sewer, he is pushing on it with all his might to loosen it. When he actually removes the grate, he pulls it off, instead of pushing.
Revealing mistakes: In the sewer, Rambo activates a blue light. The area remains lit blue, even after Rambo removes the blue light, revealing an external lighting source.
Revealing mistakes: Rambo attaches a blue light to an arrow. He shoots a Spetnaz soldier it. Rambo remains lit blue for about a second after the arrow is shot. When the Spetnaz soldier is shot with the arrow, nothing is lit blue. After a second or two, the entire scene is lit up blue. It is obviously an external lighting source being used.
Revealing mistakes: The Spetnaz soldier picks up a blue light attached to a bomb. The level of lighting in the area does not change, even when he moves the blue light, revealing that the lighting is coming from a different source.
Continuity: When Rambo is fighting the Spetnaz in the underground caves, he shoots one of his explosive arrows, however, two different explosions go off instead of one.
Continuity: Rambo is shot in his right leg, in the quadriceps. He gets up, putting his weight on that leg, and manages to walk over to the army tank without much trouble.
Continuity: In the scene where Rambo is asked to join the Afghanistan soldiers in the game where they use a sheep, at certain times during the game, the sheep looks like either a dead sheep, or a fake sheep with stuffing in it, as can be clearly seen when Rambo picks it up off the ground.
Revealing mistakes: In the scene where Rambo puts a timed explosive in the watery caves and ducks under the water, the bomb explodes. When it goes off, you can clearly see to the right, the fake rock wall, shaking from the explosion.
Revealing mistakes: In the scene in the cave where Rambo is pushing out the remainder of the explosive arrow from his side after being wounded by one of the Russian Soldiers, you can clearly see the square fake patch of wounded bloody skin covering his real skin when he pulls out the remainder of the explosive arrow.
Factual errors: The AK74 assault rifle that Rambo is using during the showdown at the Pakistan border (with the Hind D) has a U.S.-made MP203 grenade launcher fitted under the barrel instead of the Soviet GP-25 used by Soviet troops during the real-life occupation of Afghanistan c. 1979 - 1988.
Continuity: In the scene where Rambo gets to Peshawar (Pakistan), he gets into the shop and receives his equipment. When the other guy ask him "what's that?" (looking at the blue light) Rambo is activating the blue light with his right hand but when he's showing the blue light to the guy, the blue light is in his left hand.