When Karen first picks up Michael, her car's window is shattered by gunfire, yet intact moments later.
The bolts of light from the weapons fired in space always seem to take pretty much the same time to move across the screen, no matter whether they're supposed to be moving a few hundred feet across the front of a space station, a few miles across a city, or several hundred miles from orbit to Earth's surface.
When Michael arrives at the restaurant it's supposed to be October 6 or 7, but the wall calendar behind the cash register is showing the 12th of some month.
October 1992 started on a Thursday and had 31 days. The farmer's wall calendar shows the month starting on a Sunday and just 28 days long.
Gun noises and muzzle flashes.
Towards the end of the movie, when Michael's mother is about to leave for the hospital, the car containing the aliens is pulling up to the house ... and you can see the shadow of the film crew on the street (lower-left portion of the screen).