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.
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.
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 Teasle talks to Trautman for the first time, Teasle is wearing a winter coat over his police uniform. At one point the brown lapel of his police jacket is sticking out past the collar of the winter coat, but in the next shot it's tucked underneath, and he didn't have time to fix it.
Continuity mistake: When Rambo is driving the army truck he rams the police car off the road. In the shot just before the police car hits the stationary car the passenger side windows are open and police are shooting at him through these windows. But in the next shot just before the explosion the cars windows are closed.
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.
Continuity mistake: When Rambo is being pursued through the forest and comes upon the cliff edge, the water at the bottom of the gorge changes direction of flow several times. It is first seen as flowing left to right, from Rambo's point of view. The very next shot shows the water flowing right to left. It reverses direction twice more in subsequent shots. (00:24:00)
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: The rock thrown by Rambo at the helicopter doesn't actually break the windshield at all. For a very short instance (one or two frames) you can see the rock bouncing off the windshield which is still intact. The next frame is cut in (just look at the position of the pilot in the background) - the glass is now broken. Some shots later, when Galt has fallen out and the helicopter leaves, the windshield is intact again.
Continuity mistake: The sheriff left his hat in his upside down car. He suddenly has it at the gorge.