Continuity mistake: The first footprint - the one Nick is standing in - is clearly smaller that those shown from the helicopter (watch the toes). (00:11:05 - 00:12:25)
Continuity mistake: Nick and company are in a plane after leaving Tahiti. A soldier goes up to the colonel and tells him about the fishing trawlers that were pulled under. Just after that, the camera shows three guys sitting down that look up. In the following shots those guys are gone. (00:19:50)
Continuity mistake: When the Mayor of New York is talking to the crowds and people can feel the ground bouncing, Godzilla is a fair bit away, but when she is stomping through the streets the people don't feel it at all - shouldn't they be thrown into the air from that proximity? (00:26:25)
Continuity mistake: The mayor is giving a speech as Godzilla arrives in NY. There are five microphones in front of him. They move between shots, most noticeably the blue and yellow ones in the middle. (00:26:30)
Continuity mistake: When Nick (Animal) first goes after Godzilla to film him, he grabs his camera and chases the lizard. There is a fire hydrant that is shooting tonnes of water and the next shot it's stopped and vanished entirely. (00:28:31)
Continuity mistake: As Godzilla is about to step on Animal, we see two cars are directly behind Animal (a yellow taxi and a gray car). Each shot of Animal from the front as the monster approaches (and he's trying to get the tape locked into the camera) shows portions of the cars. But in the side shot of the foot as it lands, no cars are right behind Animal at all. (00:29:50)
Continuity mistake: When they are tracking the monsters movement towards the pile of fish, on a computer screen the icon representing Godzilla moves forward and in the next scene repeats over the same territory. (00:47:00)
Continuity mistake: In the scene when Victor is chasing Nick after crossing the airport sign on the road, you can see the steering wheel of the van is being held in Victor's right hand from his point of view inside the news van, but in the next shot Victor is holding the steering wheel with his left hand. (01:09:40)
Continuity mistake: Godzilla noticeably changes size throughout the movie. For example, she is shown lairing in a subway tunnel, but she cannot fit into the Hyde Park tunnel (taxicab scene), which is significantly larger than a subway tunnel. Also, compare the size of Godzilla's eye next to Matthew Broderick during the fish scene and Godzilla's death scene. The eye is way bigger in the latter.
Continuity mistake: Near the end of the movie there are 3 US Navy F-18 planes. The lead plane shows a graphic of 4 missiles, 2 of which he launches at Madison Square Garden. Then later, and without landing, the 3 planes fire at Godzilla, 2 missiles from each plane on both passes. This means the lead plane fired 6 of its 4 missiles.
Continuity mistake: When Godzilla is chasing the taxi, the taxi crashes through a chainlink fence. As it rounds the corner shortly after going through the fence, the sign on top of the cab comes loose and is being held loosely by a wire toward the front of the cab. You can clearly see that the sign is loose, but a few shots later, the sign is attached firmly in place atop the cab.
Continuity mistake: During the scene right after the F-18's destroy Madison Square Garden, Godzilla goes after the taxi and Nick tells Phillipe to turn the car around. The problem is that on the street you can see that the first time they went through, Godzilla left some huge footprints and destroyed the street. When they turn around and drive up there a second time, the street is perfect. This happens again when they are stuck in the Hyde Park Tunnel and Godzilla shoves a claw into it and breaks up the road right in front of the taxi, but when Phillipe drives forward and then puts on the highbeams, the road is fine.
Continuity mistake: When the team is travelling to the cannery ship you see several people and a few vehicles going the other way. A helicopter flies over their heads and the camera shot from behind the chopper shows there is no one on the road heading away from the ship.
Continuity mistake: The ground does not shake every time Godzilla comes - only in some of the first scenes. And only when approaching - not when he is walking away.
Continuity mistake: Watch the roads during the chase scenes. They go from soaking wet to dry to wet again scene to scene, in the same street as they turn around.
Continuity mistake: When the reporter is chasing Godzilla in New York, just before he stops his hat falls on the ground between him and a taxi. But in the next shot of him when Godzilla is about to crush him, the hat is gone and is never seen again.
Continuity mistake: In the scene where Mathew Broderick is loading his luggage into the taxi, Hank Azaria is seen opening and holding an umbrella. When he crosses the street to steal a truck, he drops the umbrella, but on the wide shot that soon follows, there is no umbrella on the ground.
Continuity mistake: When Godzilla goes to eat the pile of fish, it only takes about 3 mouthfuls from the top of the pile before being chased off. In the later shot, all the fish have been eaten.
Continuity mistake: When Viktor and Audrey fall from the ventilation ducts, Viktor's camera goes skidding across the floor about 6 feet or so away, yet when Jean Reno comes over to step on the camera it is within a foot of where Viktor fell.
Continuity mistake: They go into the broadcast booth in Madison Square Garden. While Audrey is broadcasting, the French guy moves the vertical blinds to his left to look out the window and sees a dinosaur raise its head. Just after that the view switches to the dinosaur's side and he is now holding the blinds to his right.
Answer: Everyone was so focused on the nest in the Garden, they all forgot about Godzilla.