Other mistake: After the veterinarian throws blood all over the floor, we see clean spots appear on the floor in the shape of Sebastian's feet as he walks through the blood. Somehow he never has any of it stick to the bottom of his feet (even when he's in the puddle).
Plot hole: The elevator to enter the lab requires a visible-light thumb scan, but Caine enters the lab (and apparently not by following someone) after he has become invisible. A fingerprint is not sufficient for the type of scanner shown. The gloves he wears would also not follow the contours of his fingertips closely enough to copy his fingerprints.
Deliberate mistake: Elizabeth Shue uses a drawer handle as an electromagnet. OK if it's really a magnetic material but lab furniture is generally made of aluminium or stainless steel which is not. There is no way that they would use an iron handle in a potentially wet, and hence corrosive, environment such as a freezer.
Other mistake: Elisabeth Shue uses the blowtorch to set off the fire sprinkler in the hallway, but later there is a raging inferno in the lab with all the important data and equipment and there's not one sprinkler, nor any alternative "electronic equipment friendly" automated fire suppression mechanism such as Halon gas.
Plot hole: Caine's skin becomes visible when it chars, for no reason consistent with the other invisibility. Further, it drops off in an impossible way (since there's no indication the invisibility otherwise changes metabolism/healing). Caine acts far too healthy for someone so severely burned. Finally, the extreme damage to skin and muscles that this implies is not seen when he becomes visible. (Even if the material flaking off is clothing, most of the arguments still apply; burned clothing would adhere to burned skin, and would provide little to no protection from the fire.).
Factual error: There is no way for the vet and Shue's characters to intubate Dr Caine when he was attempting to come back from phaseshift. He had not completely re-appeared and it would be impossible to tell his airway from his esophagus.
Deliberate mistake: When Sebastian goes to his employer's house to kill him, the man is standing by his pool smoking a cigarette. When the boss blows smoke in Sebastian's direction, Sebastian appears and scares him. Since Sebastian is invisible you shouldn't be able to see his pupils, only an outline of his eyeballs, but you can see the pupils.
Continuity mistake: When Kevin Bacon's invisible character shoots another character in the chest with a dart, the dart changes position. First it is on the upper left side of the chest, then it is in the exact centre.
Factual error: The speed used to administer the serum to Sebastian is not close to the reality. At that speed the vein would have exploded.
Continuity mistake: When they first inject Kevin Bacon with the stuff that makes him invisible, he thrashes around in pain. He lunges to his left breaking the strap holding down his right arm. In the scenes that follow his right arm is still strapped in. They even unstrap him to let him up.
Continuity mistake: In the end of the movie you can see that the doors of the elevator are almost closed. But in the next scene when Linda shoots him with the flamethrower, the doors are open again.
Other mistake: During the scene when Elizabeth Shue burns Kevin Bacon with the flame thrower, she has blood on her shirt. When she shoots the sprinkler head the blood is gone.
Factual error: Duct tape would not stick to bloody skin at 40 below zero, and probably not at higher temperatures either; again because of the blood.
Continuity mistake: When Isabelle (the gorilla)'s body hair is returning, you can see Linda (Elizabeth Shue) touching it. In that shot, the leather belt above Isabelle's body actually seems to be hovering above her - it is not resting on her.
Factual error: The braking system on lifts (elevators) is designed to stop a free-falling car safely and quickly (using gravity and a wedge system). It would not take a long time to stop the car or break up as shown in the film.
Continuity mistake: When the redhead spilled the blood all over the floor to see if he was coming at her there is a little area to the left of the screen he could walk on without her seeing it. The next shot it's gone.
Continuity mistake: When Dr. McKay pushes open the freezer door, she is standing behind the row of wires still connected to the door. A moment later, without moving, she is on the other side of them.
Continuity mistake: When Kevin Bacon gets up and the sticky sensor things rip off his body, they snap backwards and disappear into thin air.
Continuity mistake: In the scene where Linda tapes up Matt's wound, she is seen pulling a large strip of duct tape almost all the way across his stomach. Later, when they first start climbing in the elevator shaft, Matt's shirt rides up and the tape is gone.
Factual error: When we first see Caine (Bacon) enter the military base, there are Willy's Jeeps used by military personnel. By the year 2000, the Willy's Jeep was long-since replaced in the U.S. Military by the HUMVEE, which we also see in the film.
Suggested correction: It's not a Willy's jeep. It's a Ford M151 Mutt, which was still in occasional use at the time of filming.
