Just prior to the big chase, Majestyk pulls the truck into the driveway and parks in front of the house. He then unhooks the trailer and leaves it behind the truck. When he runs out of the house and jumps into the back of the truck as the woman drives it away, the truck is facing the other direction and the trailer is not in sight.
During the chase in the canyon, the left headlight is alternately there or missing.
At the cabin, when Majestyk hides from Frank by jumping up into a corner of the log cabin, his feet are not quite two logs up from the stone foundation, yet when Frank looks down from the roof into that corner, his point of view shows two full logs and no feet can be seen. Immediately afterward when Majestyk jumps back down, his feet can be seen starting from the same position, less then two logs up, as he jumps back down. His feet should have been visible from Frank's viewpoint on the roof.
During the car chase scene, Majestyk is loading his shotgun in the bed of the pickup as Renda and his henchmen close in on the truck in their two cars, and the view from the lead car shows it closing to within 15-20 feet of the back of the truck, then the view switches to Majestyk's view from inside the truck bed and both pursuing cars are still a couple hundred yards back, then the view shows Majestyk kicking open the truck's tailgate and the lead car is again 15-20 feet behind.
During the shoot-out scene to help Renda escape, the front police escort car is practically engulfed in flames entirely. A moment later when the station wagon crashes into it, only the back is ablaze, the rest of the car has no fire damage whatsoever.
Bronson is cast as a Vietnam veteran, which means he would have been in his 40's or 50's during the war. That would have been highly unlikely unless he was a career soldier, which he obviously is not. It would have been much more appropriate for his character to have been a veteran of World War II or the Korean War.
The first to appear on scene during the breakout is Lundy. He stops the bus carrying the prisoners by standing in front of it and kills the driver by firing three shots. After killing the driver he runs for cover and fires four more shots with the same handgun. A few minutes later Lundy is shown crouching behind a car while shooting at a deputy. This time Lundy has two handguns whereas he only had one previously.
When Majestyk crashes through the back windshield of the Mustang to escape, the stuntman is clearly visible.
Before Majestyk punches Frank into the bedroom of the hunting cabin, you can clearly see it is a stunt double as his hairstyle does not match Al Lettieri's character.
When Majestyk pushes the red Plymouth Fury off a mountain road, you can see a front shot of the car, where the actors are replaced with stunt dummies, before it rolls down the cliff.
When Majestyk punches Renda while in the hunting cabin the stunt man, seen from behind, has straight hair unlike Renda who has curly hair.
During the chase in the canyon, a safety cable can be seen attached to the bad guy's car front bumper.
Just after Majestyk and Frank are fighting in the back seat of the car, Frank shoots the back window. Majestyk pushes him out and escapes through the broken rear window. As he runs away from the car, the shadow of the film crew is briefly seen at the bottom of the screen.