Factual error: The cars on the ferry would be secured by chains and should not have moved so easily across the deck. Admittedly they would break free at some point depending on the tilt. They had time to secure them, as they were already there before they arrived.
Visible crew/equipment: When Ray, Rachel and Robbie run aboard the ferry, and the camera follows them from behind, its shadow can be seen on the right side of the screen projected on cars and people. (01:03:39)
Continuity mistake: When the asphalt in front of the church starts to crack and move and Ray gets on the sidewalk, his legs are positioned in different ways in two different shots. (00:22:36)
Suggested correction: With the way Ray moves his feet (hopping/dancing quickly from one foot to the other), I don't see a discrepancy.
If you look closely in the first shot he keeps one foot on the asphalt and the other one on the sidewalk, in the other shot he has both of them on the sidewalk, so the discrepancy is very evident.
Continuity mistake: When in their home basement, when the lightning starts they take shelter in the utility room and the door is a cross and bible style door that opens out. When Ray shuts the door against the fire he pushes it closed instead of pulling it, and it is a plain flat door. If there were two separate doors the fire wouldn't be burning through the still intact cross and bible door that Ray opens properly in daylight.
Continuity mistake: When they arrive at the ferry port a man throws something at the windshield which hits the top, and the screen around it shatters. In the following shot the car hits a pole and the damage has moved to the middle, and it's now a perfect hole.
Other mistake: When they arrive at the ferry port the crowd try to steal the car and it all turns violent, as if no one's seen a car for a while, but when they arrive on foot at the ferry there are several cars already on it, and no one bats an eyelid. The cars at some point must have driven through the crowd with no problems. Also the cars are taking up much needed space on the ferry.
Suggested correction: The cars could have been on the ferry before the crowd arrived. Or at least have been standing at the front when the ferry arrived. Besides, the fight over the car is for people not going onto the ferry obviously, but going somewhere else.
Visible crew/equipment: As Ray drives and Rachel screams, the camera crew and equipment are reflected in the window.
Audio problem: When Robbie helps the people onto the ferry, his speech is out-of-sync whilst he is talking. Most noticeable when he says "Hold on".
Continuity mistake: When the movie ends, Rachel runs to hug her mother and a strong wind blows large amounts of leaves a meter up. A frame later, from a different angle, the wind is milder and the leaves barely move.
Continuity mistake: When Ray puts his feet on the sidewalk when the intersection moves, there is a blue car in front of him that is on the side of the moving intersection. Three shots later, when we are shown the moving intersection, the blue car disappears. (00:22:40 - 00:23:55)
Continuity mistake: When the tripod is taken down, the lights are flickered out on it. But in a couple of scenes later, the lights are working again on the tripod, right before the alien crawls out of the hatch.
Continuity mistake: This movie has to take place over at least 4 to 7 days for them to walk from New York to Boston. When they arrive in Boston, he has absolutely no facial hair growth.
Audio problem: When the tripod walks over the hill at the ferry scene it walks over two trees. However, the first tree it stepped on doesn't make a cracking noise as it should. The second one does.
Continuity mistake: When Rachel is watching the floating corpses in the river, the shots alternate back and forth between a wide angle where she is standing still and wind is not blowing, to a close-up where she is sobbing, moving her shoulders up and down rhythmically and her hair is moving rapidly.
Continuity mistake: When the movie ends and Ray meets his family, the street keeps swapping from sunny to shadowy back and forth.
Continuity mistake: When Ray looks at the tripod, he stands beside a car that's plain and labeled Maxium. But when Ray runs away, that car is now covered with droplets of water. (00:26:05)
Continuity mistake: After the tripod appears from the hole in the ground, it bellows and pulls out its rays. In the next shot in the window's reflection, the tripod is seen pulling it out again. (00:26:00)
Continuity mistake: When the intersection moves, a van is parked five feet away. When the intersection is destroyed forming a hole, the van is parked closer to the hole, allowing it to be thrown in. (00:23:10)
Continuity mistake: Ray runs out of the house looking for Rachel and moves away some weeds blocking the door. When the angle changes the door is spotless.