When Max is going to get K.W. just prior to the Dirt Clod War, his hood is down. When he returns to Carol and Douglas, (just prior to being hit with a dirt clod) his hood is up.

After Wolverine arrives at 3 Mile Island he approaches through a thick fog. Above him are a series of conveyor belts that are used at a coal power plant, not a nuclear plant such as 3 Mile Island. The belts are unique to coal mines and coal power plants, and would not be found at a nuclear power plant. The filmmakers obviously couldn't film on the site of a nuclear plant, so filmed on a coal plant to fill in.

At the beginning of the film, Hoffman retracts the walls of the room where Agent Strahm has been squashed. The whole body drops to the floor. However, Strahm's hand remains untouched. Now considering the walls shut completely, his hand would have not survived if they were powerful enough to crush his body.

When Katie goes downstairs in the scene at the end, the alarm light (green) is off. When she comes up with the blood on her shirt the alarm light is on.

Gallaxhar scans the galaxy to find the missing quantonium. The scanner zooms in on earth, showing it to be very close to the center of the galaxy. Earth is actually nowhere near the center of the galaxy; it's located much closer to the outer edge.

When they fall off the house and can't get back on it Russell isn't wearing a backpack. After they decide to walk the house to the falls, Russel has his backpack.

Rham attempts to give CPR to Shaun San Dena after the encounter with the Lamia. He uses completely wrong hand positioning, would more likely break her collarbone than stimulate her heart, and does the CPR for all of about 10 seconds, which would be useless. There's evidence his character was trained in CPR, as he listens for breath and watches for chest rising properly, so it is not likely he was just making it up as he went along. A person trained in CPR would at least put their hands in the right place. He was not just a couple of inches off, but not even close to where the hands should be placed. Also, CPR must be done continuously until medical aid arrives, not for 10 seconds.

During the "nude" scene on the beach, when Shane is asked to drop his drawers, he wears shorts initially, but then in a subsequent shot right before the "reveal", he is wearing pants.

Contrary to what the movie states, priests can be elected Pope - they are simply elevated to the rank of Bishop before taking the office.

Woody Harrelson locks himself in the booth at Pacific Playland and locks/closes the security screens on three sides. After he is surrounded by zombies, one of the side cages has been pushed opened a bit, leaving quite a gap. The scene pans around to various angles as Woody fires away, and in a subsequent shot, the screen is shut again. With both his hands full, he couldn't have shut it.