At one point a radio report says that deaths will rise at four times the rate in eight days, and by a hundred percent after ten days, as if this is even more. However, to rise by a hundred percent only means that it doubles.
One of the characters refers, in the start of the film, to Orson Welles' War of the Worlds broadcast as a hoax. In fact, that broadcast was announced as a work of fiction as normal for a Mercury Theater broadcast.
When arriving at Deb's parents' house in Scranton, Deb comments that West Virginia (where her parents and brother were camping) is only 100 miles away. Even though we don't know where in West Virginia her family was, the closest point in the state would still be approximately 200 miles from Scranton.
Scranton is 122 miles northeast of Harrisburg; it does not make sense traveling from Pittsburgh (in the western most part of Pennsylvania) to drop a character off in Scranton before swinging down to take another to Harrisburg.
When the bald zombie is splashed with acid, it eats away half of his head within seconds. A splash of very strong acid will only burn the skin. To dissolve half a head would take soaking in gallons of acid for a very long time.
When the boy zombie is hit by the arrow he's thrown back and pinned up to a wall. HIgh speed projectiles like bullets and arrows tend to quickly penetrate the body. There is not nearly enough mass in such a projectile to transfer the amount of momentum required to jerk a body several feet back and up against a wall. Secondly, the connection of the arrow to the wood in the wall is not strong enough to support the weight a body. The arrow would snap off or pull out of the wall.
The Professor must really like his Bourbon. He was out of booze, but when they were in the warehouse where the leader told them to take what they want, there were cases of Glenfiddich scotch in the background. He was still looking for booze later.
The film supposedly takes place on October 24/25 yet you can hear peeping frogs in the background when the RV stops after running over the first four zombies. The peepers "peep" during their mating cycle from March to May, not in late October.
At approximately 17:30 into the movie, an oncoming car beeps and passes by the van where everyone is introducing themselves. As we look at the passing car, its headlights reveal outside that the trees aren't moving and the van we're in is actually stationary.