Blooper

(at around 14 mins) When Ellis shoots the waiter in the ambulance, blood does not spill on Alex. But in the next shot, her neck has blood spattered on it.

(at around 18 mins) When Ellis and Nightingale are getting cleaned up in the locker room before the mission, the blood disappears and reappears on Ellis between shots.

(at around 14 mins) When he shoots the Zombie in the ambulance, Ellis' gun switches from the left hand to the right hand.

(at around 36 mins) When O'Conner is looking at his shaking hand, the Sergeant Major turns and lights him up with his weapon-mounted flashlight (which anyone trained with a gun would never do since you are pointing your gun at your comrade). When the Sgt Major turns, O'Conner's face lights up from the flashlight. The camera cuts back to the Sgt Major and he turns to continue walking. When it cuts back to O'Conner, his face is still lit up from the flashlight.

(at around 4 mins) When Tracy's on Professor Curien's operating table, the position of her feet changes between shots.

The Special Forces (Army) soldiers were wearing Marine camouflage fatigue uniforms.

Dalton is a Sergeant/Sgt Major (from the scene at the base where the Colonel is giving them the mission brief). Henson and Bart are both Lieutenants and therefore more senior (Henson - Rodriguez addresses her as Lieutenant, Dalton - Ellis calls him Lieutenant in the last scene). Yet when the troops are entering and exiting the van, Sgt Dalton takes command. When they arrive at the college, it is Sgt Dalton that splits up the group (one of the lieutenants should have done this). When they are split up, both of the lieutenants are in one group and Dalton leads the other. In reality, if there are two lieutenants in such a small group (unlikely), each lieutenant would lead separate groups.

There are no females in any Special Forces unit.

A fat man, like the "Private", would have difficulty staying in the military. He wouldn't have a chance of getting into Special Forces.

(at around 1h 1 min) When Morgan and Ellis enter the room where the first zombie is locked for research, during close-ups the actress's own right cheek can be seen through the mouth opening behind the fake teeth.

(at around 1h 27 mins) At the end Morgan and Ellis leave to Los Angeles and cities are smoking, you can see smokes are not moving in the background.

(at around 1h 2 mins) When Ellis shoots the original zombie in the head with the shot gun, the blood spatter hits him in the face. When he wipes it off he pulls the blood down across his face and mouth. When he speaks you can see the zombie's blood on his teeth. Earlier in the movie, Nightingale tells a character not to put something in his mouth cause it had infected blood on it. If this is the case, the blood that got in Ellis' mouth would have infected him.