Goofs

Nick is wearing a three-piece suit when he goes to the seminar, but when he wakes up after the accident, he is only wearing a two-piece suit, not the vest. Nick tried to put on the vest when he was hurrying to leave his apartment. It was too difficult so he threw it aside.

In the movie, the building disintegrates because the invisibility effect makes the physical matter unstable. The same effect doesn't apply to Nick or the clothing and objects he is carrying.

When Nick wants to be seen, he wraps outer clothing over himself. But when he's not trying to be visible, he still wears clothing in the film, yet he cannot be seen. It would be impossible to avoid being seen when wearing some types of clothing, yet be seen wearing other types.

Except for the clothes that were made invisible in the same accident that made him invisible.

The role of Maitre D' is listed as "Maitre'd" (a common mistake) in the credits.

When Nick is holding the gun to Jenkins' head, he pulls the hammer back but the trigger doesn't move. In fact, the trigger is already in the firing position before Nick cocks the hammer.

An invisible man would be blind; the only way to see is for light to reflect off the back of the retina. If the retina is invisible the light would pass through. In the book, it was theorized that the energy particles that make up his body interact differently with visible light allowing him to see.

When Nick is eating dinner with Alice, he wears makeup, goggles, and a wig to disguise his invisibility, but his tongue is visible when he's talking. Making his tongue visible does not seem likely, nor was it established.

Nick often casts a shadow.

Nick's reflection in the gas station window

In a scene where Chevy Chase is smoking a cigarette, the smoke is shown going in and out of his lungs. He is speaking at the same time that he inhales the smoke.

When Nick punches Jenkins in Jenkins' office, Sam Neill flinches well before he's punched.

The first column of names in the alphabetical list of stunt credits ends with Alan Oliney, who is also credited at the top of the second column.

When Nick calls Alice to the gray beach house while he's smoking (the second puff/inhale) he starts talking while he's still inhaling the smoke into his lungs.

In the congressional hearing, Jenkings is asked a question in connection with "IG Farben" in Germany. A powerful industrial conglomerate of Nazi Germany, IG Farben was put into liquidation after the end of the second world war and split up into several successor companies such as AGFA, Bayer and BASF. As a legal entity, its continued existence was basically just a technicality until the liquidation was finally completed in 2012. It did not have any actual business dealings etc.

Most of the movie is told via flashback, with Nick narrating it on his video confessional. But how would he know about events that took place without him being present, such as Dr. Wachs' murder or how the building accident occurred in the first place?