Continuity mistake: In the hotel room, David watches TV and next to the TV are plastic cups. In the shots facing David the cups are right up against the TV and there's a phone book lying on top of the TV set. In the shots facing the TV, the cups are further away on the dresser and there is nothing on top of the TV set. (00:48:05)
Continuity mistake: At the hotel, David's blue shirt is lying straight on the pillow by the headboard when he opens the door to let Allison in. When she sits on the bed to make the calls, the blue shirt isn't straight in this shot. Also, the Chinese food containers' positions on the table in this shot differ from the shot when David stands up after slamming the phone down. Then when he sits at the table the containers' position change again in the next couple of shots, as does his blue shirt. (00:48:45)
Continuity mistake: At the hotel when Allison knocks on the door David goes to open it, and the round table's 'folding sides' face a particular direction. In the next shot Allison puts the shopping bag on the table, and the 'folding sides' of the table are facing another direction. (00:48:50)
Audio problem: In 1943, a top secret Naval experiment went wrong and David was sent forward in time to 1984, with his friend Jimmy. In 1984, David and Allison, a girl fom the present day, are staying in a hotel room. David picks up the talking travel alarm clock and fidgets with it. Yet, in the shot of Allison the alarm clock is still on the nightstand between the two beds. Then as he puts the alarm clock back on the nightstand, in the shot of Allison, the alarm clock is on the nightstand even though we hear the sound of him actually placing the alarm clock down. (00:54:25)
Continuity mistake: David and Allison pull up to the corner across the street from David's father's old place. In the close-up of them in the car, the surrounding area around the car is completely different than the area shown around the car in the wide shot. Also in the wide shot we see cars parked to the right of the screen. After crossing the intersection, they pull into his father's old place, and we see the same sidewalk across the street, but none of the cars that were parked there in the previous shot are there now. Then when they pull away, again the parked cars are different. (01:02:20)
Revealing mistake: Going to his father's old place, David and Allison turn right on the corner, pass some stores and then turn left to drive into the lot of the Texaco station. The reflection shown in the stores' windows across the street is not at all what is supposedly across from those stores. Also, when they start to pull away from the station a set of studio lights are reflected in the side back window of the car. (01:02:40)
Continuity mistake: David and Allison drive away from the station, after David learns of his father's death. When the camera is just on Allison, sitting in the passenger seat, the view of the background behind the car is very different than the view when the camera is just on David. (01:04:55)
Continuity mistake: After crashing through the guarded barrier of the base, David drives the stolen pickup truck and burning debris from the electrical storm falls onto the hood of the truck. In the next close-up the burning debris is shaped differently. Then after they crash through the wall, in the wide shot there is no burning debris on the hood. Yet, in the next close-up there's plenty of burning debris, but then in the next shot there is no burning debris again, just a smoking engine. The building debris surrounding the truck and behind it, in the first shot differs from all the building debris in the second shot as well. (01:21:50)
Continuity mistake: David's hairstyle changes throughout the movie multiple times between consecutive close-ups and wide shots. For example, at the base when he's in Dr. Longstreet's Lab, as he speaks with Dr. Longstreet David's hair continuously changes between shots. (01:23:00)
Continuity mistake: As David walks with Dr. Longstreet, just before he enters the vortex, the man behind David is carrying David's helmet. In the first shot the helmet is right side up in the man's hands, but in the next consecutive shot, the helmet is held upside down. (01:27:40)
Continuity mistake: After David has gone through the vortex, he grabs an axe and starts to hack some of the equipment. In the next close-up shot he stands at the doorway without an axe in his right hand, but in the next wide shot the axe is back in his hand. (01:31:50)
