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.tw_stuart
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.).
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.
Revealing mistake: Sebastian Caine wears a latex mask and latex gloves in order to appear near-human. The mask he wears is fairly long, and covers his neck, and the tops of his shoulders and collarbone. However, there is a scene in which Linda and Matt are helping a nauseous Sebastian reach the toilet, where he vomits (invisible fluid) into it. In this scene, when Sebastian breaks free from them and runs to the toilet, we can see that his arms and chest are also visible, skin-colored. The mask he wears only reaches the very base of his neck, so it is possible that the actor playing the invisible man did not realize that the tops of his arms and chest were visible. (00:49:20)Tom