Factual error: No electricity, yet the washer is running.
Factual error: After taking off from Bangor, the pilot pulls back on the flight control bringing the plane up to level flight. However, after taking off, a plane is "nose up" and would require pushing forward on the controls to bring the nose down to level. This is also evident by looking at the attitude indicator (circle with top half blue and bottom half brown). The white line indicates the horizon and you can watch the indicator show the plane's attitude coming from below horizon (nose down) to the horizon (level flight).
Suggested correction: It is possible that as the pilot was watching the airport disintegrating and vanishing, he accidentally or deliberately let the plane nose go down because this sight was so extraordinary that he might have forgotten to fly the plane properly or wanted to get a better view.
Factual error: At the end when the oil in the cavern is burning there is no sign of smoke. With a fire as large as it appears to be, everyone in there should be choking to death, yet they don't even seem the least bit bothered. Forest Whitaker should have also been roasting over the flames, yet he is unscathed.
Factual error: When Helen is launching the video that shows the girl turning into worms (the killer's next victim later found at the dumpster), typing "tomorrow.avi" as she does would have returned an error in Linux. She should have typed "call tomorrow.avi" to launch the video. (00:43:00 - 00:44:00)
Factual error: When Malcolm's head is ripped off by the corn stalks, his spinal cord is absurdly long.