Other mistake: When Columbus is face-to-face with the clown zombie, he looks up at Wichita, who is on the ride, stuck at the top of the tower. Columbus looks almost straight up at her, but when Wichita looks to Columbus for help, she should look almost straight down, but instead she looks straight ahead. There is no other reason why she would have looked straight ahead because a) Columbus was directly below her, b) Little Rock and Tallahassee were to her right, and c) she almost perpetually had her eyes on the zombie climbing the tower towards her.
Other mistake: Most of the time when driving, the windows are down (possibly so no camera reflections are seen) but their hair mostly doesn't move and there is no wind noise in the truck like there would normally be.
Other mistake: After Columbus wakes up and realises the girl he let stay the night has turned into a zombie, he repeatedly hits her over the head with the commode top, but in the next shot, it is clean as a whistle - there is no blood or head matter on it at all. Also the bottom of the lid is real with grooves and crevices but after the second hit in the living room the bottom ridges are perfectly oval and smooth.
Suggested correction: He hit her in the place where there is hair on the head, he left no wound there, why in the world should be marks on the lid? It would be a mistake if there were marks after the impact shown.
Other mistake: When Columbus and Tallahassee open the back of the Hostess truck, a bunch of Snowballs fall out. During the shots from the inside the truck, on the right side, you can see some packages of Twinkies. It might not be easy to make out of the shape, but you can see the label on the package. I guess they should've done a more thorough search of the truck. (You might need widescreen to see this).