Visible crew/equipment: During the motorcycle chase Rambo jumps over the train tracks, if you look close you can easily see the ramp
Continuity mistake: When Rambo approaches the police road block, the truck's windshield is penetrated by bullets. When the truck crashes through the barricades, the bullet holes are gone. They reappear on the next shot, but at the wrong places, then disappear again.
Continuity mistake: When Sylvester Stallone is in the stolen army truck and crashes through the police road block, the truck becomes airborne. Upon landing, the gas tank is clearly separating from the truck, but in the next shot, the truck and gas tank are together.
Visible crew/equipment: In the shot of the stolen army truck crashing through the police road block, you can see a camera mounted inside the truck. Look in the small window on the rear wall of the cab. (Apparently both this shot and the shots from inside the cab were done in the same take.)
Continuity mistake: Following his encounter with Rambo in the woods Teasle has a long bloody cut on his lower face. When he returns to his office the cut is completely healed and gone. But when he sits down in the bar with Trautman it is back. After this scene it vanishes for good so I presume the bar scene was originally intended to be inserted before Teasle returned to the office.
Continuity mistake: When Rambo blows up "The Outpost", Rambo is in an alley and runs for cover behind a mail box. A couple of shots later Rambo does this all over again, but this time the shot is reversed.
Continuity mistake: In the scene when the gas station blows up, watch the cars parked in front of the "Kool Lights" advertisement. These two cars explode (for no obvious reason, by the way) after the police officers have gotten out of their cars. They run away from the explosion and leave their police cars behind. Next shot, the same two cars in front of the ad explode again.
Factual error: Col. Trautman should be wearing his rank insignia on the flash (small patch) on his beret. All officers wear their rank on their flash, enlisted men wear the unit crest. (This error was corrected in Rambo II and III.)
Continuity mistake: At the onset of the film in the police station, Rambo has a few days of facial hair (also evidenced by the fact Teasle and the other officers 'wanted to shave him'). After Rambo escapes and a few hours later is about to start climbing down the side of the mountain after he hears the other officers and dogs closing in on him, look at the close-up shot of his face just as he looks back and sees that the tracking dogs are very close. Rambo now appears clean shaven. Highly unlikely he stopped to shave.
Continuity mistake: When Sherrif Teasle is chasing Rambo on the stolen motorcycle, Teasle drives his police cruiser through a small ravine. The car hits ground hard and the lens to the driver-side front turn-signal can be seen popping out of the fender. The lens is mysteriously back in place in all subsequent shots.
Visible crew/equipment: At the beginning of the movie, Sheriff Teasle escorts Rambo to the outskirts of town. As the sheriff drives off, the boom mike is visible in the reflection of the car's right rear passenger window.
Continuity mistake: When Deputy Galt falls off the helicopter, the close-up shot reveals he still holds his rifle. A split second later (distant camera), you would expect to either see him still holding the rifle or see the rifle falling away from him. However, the rifle has disappeared.
Revealing mistake: When Rambo throws a rock at the police helicopter and knocks Galt out, you can clearly tell it's a stuntman. Galt is in his 40s and overweight. The guy that was falling looked like he was 25 and was noticeably thinner.
Visible crew/equipment: In the scene when Rambo jumps on the hood of the army truck you can easily see the outlines of the cushion they put under the hood to ensure a soft landing.
Continuity mistake: When Rambo has Teasle up against the tree with the knife the knife is right under Teasle's throat, but in the next shot the knife is to Teasle's right without Rambo moving it.
Continuity mistake: When Rambo crashes through the road block in the army truck it's still daylight outside but when he's approaching the gas station it's nighttime. How could so much time pass when he was within minutes of town when he went through the road block?
Factual error: The military cannot be used to help execute civilian law except during emergencies. Rambo could, I guess, be considered an emergency however, once the national guard was called out, they would have had jurisdiction over the Podunk police department. When Brian Denehy told them to wait for them, and then subsequently to clean up their mess, he would not have been in charge at that point.
Continuity mistake: The sheriff left his hat in his upside down car. He suddenly has it at the gorge.
Audio problem: After Rambo turns onto the dirt and rock road, it looks like he is shifting gears, but the sound of the engine doesn't match.
Continuity mistake: When Rambo runs the blockade in the army truck it's still daylight. When he arrives in town it's completely dark. He wasn't that far out of town that it became night during the trip back.