One of the zombie road gang smashes the window of the Suburban. Soon afterwards, there is no damage to it.
The agent hot-wires the Suburban because the keys are lost. Later on, at the rest stop, the keys are in the ignition.
When the guys are waiting at the desert rest stop, the car door is closed on the agent's right hand, severing two fingers that fall to the ground. In a subsequent shot, his hand is visible with all fingers intact.
The 1969 Catalina has an unreadable red bumper sticker on it that appears and disappears between shots.
When Rabbit steps on the scorpion there is red blood. Scorpions do not have red blood.
The Catalina is referred to as a 1969 when it is obviously a 1967. A 1969 model would have a completely different front end and would not have stacked headlights or vent windows, both of which are present on the car in the film.
The book the sheriff is reading is "Tell Tale Heart," by Edgar Allen Poe. "Tell Tale Heart" is not a novel. It is a short story and can be found with other short stories in a collection by Poe. A movie was made from "Tell Tale Heart" but it cannot stand alone as a novel.
When the federal agents are "stranded" in the desert and the phone in the old booth at the drive-in begins to ring, a car can be seen passing in the distance.
At the end of the credits end crawl, the credit "The Producers Wish to Acknowledge the Assistance of" is misspelled as Producer's.
The jackhammer used by the convicts in 1967 is a battery powered type. In '67 the only type of jackhammer was a pneumatic requiring a large trailer type air compressor and a bull hose connecting the two.
About 20 minutes into the movie, Philips and Petty are looking off to the right and the reflector illuminating their faces is reflected in their sunglasses.