Continuity mistake: When Marlon stocks the vending machine, the camera (inside the back of the machine) shows him stocking the 1st row with brown-wrapper candy bars. He starts stocking the 2nd row with yellow-wrapper bars; Truman interrupts him for a minute (during which Marlon doesn't touch the bars at all). When Marlon continues, the yellow bars have changed to something darker (it's not just a different camera view; even barcodes are different). After another brief interruption, Marlon continues again, and the yellow bars are back. (00:35:00)
Plot hole: The first time they communicate with the "entity" in the spaceship, they find a correspondence between numbers sent by the entity and letters of the alphabet. The entity presents itself as "Jerry". Later on, the entity tells Dustin Hoffman, "Stop calling me Jerry" - and then Dustin Hoffman realizes that the number-letter correspondence was wrong, and the actual name of the entity was "Harry". But if that is true, how could they have communicated without problems before? The very first word that the entity used was "hello", which would have to be displayed wrong, since it begins with an "h" and has an "e".
Continuity mistake: When Jacquouille gets frightened by the television set, he throws a statue in it, making the TV set explode. The blankets placed over the couches as well as various objects are sucked into the set. In the next shot, the couch right in front of the TV is still covered by its blanket, which disappears in the following shot.Dr Wilson
Continuity mistake: When Mike and Jodi are walking through the "deserted" town, supposedly everyone in town has been killed by The Tall Man, when the Tall Man walks down the middle of the street you can see an old lady pushing an empty shopping cart, and a car driving around a corner in the distance.