When Andy tries to fend off the zombies that get into his store (after Chips brings the food and radio), he shoots the door and the sliding panel that the zombies use. Later when they rescue Nicole, we see the bullet holes in the door, but the panel is undamaged.
When Luis jumps onto the windshield in Ana's car in the beginning of the movie, he spits up a bit of bloody saliva. When he goes to punch the windshield in, the spit disappears but reappears precisely where he punched the glass in, even though there is a few inches separation between the two spots. Later in the sequence, the bloody spot disappears again.
When Ana is in the bathroom in the beginning, trying to get away, the lock on the window is in the down, locked, position. In the next shot that shows the window it's in the up, open, position. In the next shot she flips the lock up to open the window and opens it.
As they get on the buses to escape the mall, Michael angrily takes the keys to the boat from Steve. But later on Ana risk everything to go and get the boat keys back from Steve's pocket, which should have been in Michaels possession.
When Michael comes out of the athletes store the blood is covering his entire front of his shirt but when he gets on the elevator it's just heavily splattered and not entirely covered.
Luda's bite mark looks more like a stab wound, not a bite mark. The fact that it takes her so long to turn isn't also realistic also.
The lead character playing the nurse runs around the mall in bare feet. Although several stores are locked, she likely had an opportunity to steal a pair of sneakers.
When the survivors escape in their armored buses as the dawn breaks, they are set upon by a horde of zombies. If you look closely, when one zombie is shot down, his shirt rides up slightly, revealing a very human, very healthy looking stomach, and not at all rotten like his face.
There are two massive explosions in the movie, at the beginning while Ana is driving away from her house and at the end when CJ blows up the propane tank, but the environment is obviously not affected by the shock waves. For example, in the beginning the trees do not move; and in the latter, the water remains still.
When Ana is escaping in the car and driving on the long
street, we see a van crash into another car and throw it off the street before it explodes; though he should have been visible through the gaps between the houses, the van appears as if from nowhere at a very high speed, making it clear that he was digitally built in.
When Kenneth is fighting with the zombie in the fountain in the beginning of the movie, Ana picks up his shotgun and shoots the zombie in the shoulder. However, there's no recoil at all.
During the end of the shot of the marina (near the end of the movie), one can see a boat driving off from a dock on the right of the screen.
When the survivors are on the roof watching the helicopter fly away, right on the first "BOOM" when the camera pans away, in the background, right beyond the edge of the building, two cars can be seen driving to the left of the screen.
There's references to the Emergency Broadcasting System; that was renamed to the Emergency Alert System in the 1990s.
When Ana walks into her room, she is talking to her husband.
We see the side of her face and her mouth is not moving.
When Ana is driving through the suburban streets and passes a burning car, on the left side you can see that the adjacent street has not been wetted down to match the rest of the streets. Also, crew members and neighborhood spectators can be seen standing on the non-wet street and looking at the action being filmed.
In the beginning, when Ana is fleeing her home in a panic, a camera mount on the driver's side of her car is visible.
When Luda is giving birth the shot switches between close-ups of Andre and Luda's faces. During one of the close-ups of Andre a cameraman and his camera are visible over Andre's right shoulder.
In the scene during the birth of Andre and Luda's baby the shot switches between close-ups of Andre and Luda's faces. During one of the close-ups of Andre there is a cameraman and his camera clearly visible over Andre's right shoulder.
When Michael is about to open the door to fight the janitor zombie, a close-up of the doorknob shows wires running across the floor when there was only water, a mop, and a "WET FLOOR" sign before.
As pointed out on the DVD commentary, there are no mountainous islands in the Great Lakes like Detroit, Minneapolis and Madison those shown during the closing credit sequence which is supposed to take place on Lake Michigan.
Film is set in Milwaukee Wisconsin but the license tag on the
ambulance at the beginning reads Ontario (the actual filming location). Also, the ambulance is painted in the livery of the Ontario Ministry of Health.
The film is set in America but was shot in Ontario. During a shot of a dinner table, you can see the French logo for Kentucky Fried Chicken, PFK (Poulet Frit a la Kentucky). By law, Canadian products contain descriptions and company names in both English and French. The French side is visible.
The call letters for the Milwaukee, WI television station covering the zombie attacks shown on the monitors in the mall were KBEX. The call letters should've started with a "W." For the most part, stations west of the Mississippi begin with "K" and stations east of the river begin with a "W" (like WGN in Chicago and WTMJ in Milwaukee). This mistake is also evident during the opening credits on the sign behind the news anchors and on the microphone of the on-location reporter. However, there are some exceptions to the "K-W rule"; KDKA, the first commercial radio station in the US and its TV affiliate, KDKA-TV, are in Pittsburgh (the rules for naming stations came later). Some stations in cities located on the Mississippi river (such as Minneapolis, Minnesota, USA and Saint Paul, Minnesota, USA/St. Paul, Minnesota, USA) may have their physical facilities on the "wrong" side of the river. However, all stations broadcasting in Milwaukee start with "W".
The United States has the broken lines on the inner part of the center turn lanes, since Canada has the broken line on the outside part of the center turn lanes, as an aerial shot of a 5-lane thoroughfare is depicted in a scene where a car is seeking refuge from the zombies. The Greater Milwaukee area in real life however, has no 5-lane (center turn lane) thoroughfares.
When the group goes into the parking garage to turn on the generators they never make it. They are instead confronted by zombies who they douse with gasoline from a pump and set on fire. If there was no electricity in the garage then the gasoline pump wouldn't work.
If only people who are bit come back as zombies, then it begs the question as to where the original zombies came from.
When Ana wakes up the morning of all the chaos in her neighborhood, her little girl friend Vivian shows up at her bedroom door as a zombie, then, without so much as a growl, Vivian gently puts her arms around Luis and then suddenly attacks. For this to occur, Vivian's zombie would have had to ignore all the other people and chaos going on in the neighborhood at the time, find Ana's house, (by sheer coincidence), open the front door of the house and then open Ana's bedroom door to attack. This scenario is not likely since it is inconsistent with the behavior patterns seen in other zombies in the film, who obviously attack immediately and do not seem to have the ability to engage in higher functions, such as finding a specific address and using a door knob.
The Milwaukee transit bus driver who attempts to carjack Ana is wearing a uniform that has the New York City, USA Transit Authority's 1968-1994 "M" logos on the jacket and hat.