When Sarah sits in front of the helicopter a lot of seagulls can be seen and their shadows pass over her. When camera closes in, the gulls are gone.
During the first meeting underground, the orientation of the captain's rank on Rhodes' collar changes from one shot to the next.
Captains Rhodes, wears the U.S. Army Reserve 99th Regional Readiness Command patch and the U.S. Army uniform tape. Making him and all his men U.S. Army soldiers. Throughout the film you see them all wearing the "Bakers Cap" of the U.S. Marine Corps. They would all have had the Army baseball cap.
(Around 1.06.50) A scene shows that among Logan's subjects, there's a zombie baby. Although it's the size of a very small newborn, it has a full set of adult teeth. This short scene was removed from the 90's European video release.
When the soldiers see the zombies coming down on the platform, Rhodes escapes in the opposite direction on a cart, meeting several zombies on the way (he even hits one). These zombies are not coming from the platform as some people erroneously think (which would indeed be impossible). They come from the mine, as the mine gate has been breached (revealed in preceding shots).
At the beginning of the movie, the calendar on the wall show the month of October, beginning on a Tuesday. At the end of the movie, the November calendars begin on a Monday. Unless they skip several years, November should begin with a Friday. However, the opening scene is revealed to be a dream, so the calendar isn't real. Even if it was the memory of a real calendar, the one at the end of the movie is hand-drawn, so it could be a mistake of the character, not a continuity goof.
At the beginning of the film, when the alligator crawls out of the bank, the band tying its snout shut can be seen.
When the zombies are funneling into the bunker, the soldier zombie quickly adjusts his helmet as he enters the doorway.
An obvious stunt-double for Anthony Dileo Jr. for the scene where Miguel is thrown off of the platform by "Steele". (The stuntman appears to be Taso N. Stavrakis, who also plays Torrez.)
(around 1h 27min) Zombies have just caught a private who is still shooting on the ground. There is no magazine in his pistol.
When guns are fired in the zombie-filled caves, no flames can be seen emanating from the barrels.
In the opening scene as they fly over the supposedly deserted city, on the left middle side of the screen, a car can be seen driving down the street pulling into a parking spot.
Captain Rhodes's infantry officer insignia (the crossed rifles on his lapel) are worn incorrectly. They are worn properly vertically, with the "barrels" pointed inward.