In the scenes where Sikes is wearing the electronic helmet, the chin strap is fastened, then loose and then fastened again.
After John Brown is made into Gadget he exits the room with wires around him, but before he exits he had no wires.
When Inspector Gadget falls on top of Brenda in the building, the position of their faces rapidly changes between shots.
As John Brown wakes up after being transformed into Inspector Gadget, he falls off the right side of the table. An overhead shot of the operating room shows him on the other side of the table as he is getting back up.
The fender of Claw's limosine is clearly damaged after colliding with the gadgetmobile. However, in the next shot the damage has repaired itself.
When Inspector Gadget talks to Brenda from outside of the sky rise building, it would have been impossible for her to hear what Mr. Gadget was talking.
In the scene when Scolex brings RoboGadget to life, in the close up shots of RoboGadget's head, the collar of a grey t-shirt can be seen. But in shots where we see his body, it is all machinery below his neck.
When Robo-Gadget is going through the city pretending to be Godzilla by making the shape via his hands, from the shadow on the wall it is obvious that whatever is making it is on rods and not his hands.
When inspector gadget is fighting robot gadget on top of the bridge, for a second or two you can clearly see Matthew Broderick's stunt double's face. This happens right before Matthew calls for "time" out.
Shots inside of the Gadgetmobile clearly show the same clear blue sky and nothing mobile in the background.
A lighter can be seen in Gadget's hand when the fire is supposed to come from his thumb.
When Brenda Bradford enters Dr. Claw's office to look for Dr. Claw, a robot version of her suddenly appears. During the movie, Dr. Claw and Dr. Kramer are constantly on working on how to make an evil version of Inspector Gadget. But there is never a scene that shows them putting together a robot version of Brenda.
Gadget flies around the city with his hat contraption screaming, yet his mouth doesn't move in one shot.
When Gadget is hanging off the building at the end of the movie, a crewman's shadow can be seen for a short time during the overhead view.
At 22:40 you can see brodreck holding the tube that has the toothpaste coming out of it.
When John Brown/Inspector Gadget flys in front of Scolex's helicopter he announces For the third time Sandford Scolex you are under arrest! He only told Scolex he was under arrest one time before when he crashed through the back window of his limo earlier.
Scolex lost his left hand when it was crushed by the bowling ball and replaced with the claw but when Scolex goes to the Gadget Award Ceremony he mysteriously has his left hand which he is using to hold his cigar although it was likely it was a fake hand that Kramer made for him in order to cover up the claw so John and Brenda won't recognize him as Brenda's father's murderer.