It is stated that the zombies act independently of the central nervous system. Given this, there is no explanation for why head shots kill the zombies.
The helicopter they get into has only two blades. As they start it up, a shot of the blades starting to turn is of a four-bladed model.
After the group lands on the beach - there is a view of the Golden Gate Bridge and there is traffic driving across.
When they enter the Police station they find a man hanging there who has already turned. They decided "to take him out of his misery" with a shotgun blast to the head. In the next shot his face is perfectly fine.
The slow-moving zombies somehow manage to run in the ocean water.
When he zombies first overrun the prison, the "rifle" the heavy-set black male has is actually just a single-shot pellet gun.
The type of microscope that is being used in several of the scenes to examine zombie specimens would not deliver the magnification seen on screen. It is a common compound light microscope with a maximum magnification of 400x (1000x if Lavar Burton's character was using oil immersion which he isn't).
When the heroes escape by helicopter, the pilot is seated on the left side. All helicopters are right-hand drive.
In several of the aerial shots of the supposed deserted city, you can see vehicles moving on the streets below.
After the raft is attacked by the zombies, the next overhead shot of the coastline shows the shadow of the helicopter in the ocean.
The car that crashes down the road in the beginning of the movie barrelrolls sideways with the front to right, but when it stands still on the ground the front is to the left of the screen.
In one scene, it shows zombies climbing straight up the bridge pilings of the Golden Gate bridge. Not only are the zombies completely dry but they climb the bridge like spiders yet others in the same movie can't climb a 6 foot cyclone fence.
When the survivors enter the Police Station looking for weapons, they encounter an officer who hanged himself but turned into a zombie anyway. As they approach, Kyle makes a comment but the zombie's lips are moving in sync with the words.
Lynn gives Ashley a toy car while the girls sit in the trolley. After Lynn stands up to leave, a portion of the boom microphone handle can be seen coming into frame at the top right portion of the screen.