Terminator 2: Judgment Day (1991)

Revealing mistake: In the scene where the Terminator and the T-1000 are fighting in the corridors of The Galleria, the Terminator has fired multiple shots at the T-1000. When he gets up off the floor, the Terminator throws him into the left wall and the impact hole is already visible before he hits. (00:31:45)

Aidan2011

Revealing mistake: When the Terminator's arm is caught in the wheel and he rips his own arm off and stands up, if you look closely (slow motion can help, but isn't essential) you can see his real arm stretched behind his back under his leather jacket. (02:09:30)

Revealing mistake: When the Terminator is trying to save John from the T-1000 in the truck, he makes the jump. If you look at his face and hair while he's airborne, you can see it's a stunt double (Peter Kent). The Terminator stunt double is also obvious in other shots throughout the film. (00:35:40)

Revealing mistake: When John Connor and the Terminator are at the payphone calling his step mom, the Terminator punches the phone and puts a massive dent in it and change comes out. If you look at the bottom of the phone before he punches it there is already a dent there. [Pan & Scan version ideally, although you can just see the very top of the dent for a few frames in widescreen]. [ALSO- you can see that the area where Arnie hits the phone is merely plastic, which is unpainted to match the black phone!] (00:40:00)

Revealing mistake: During the scene where the T-1000 is in a truck chasing John Connor on a motorcycle, take a good look at the actual shot of it driving off of the bridge. The street sign is correct, but everything else is backwards! This is because they shot it backwards and flipped the shot during post production. Since the sign was so obvious, it was digitally reversed. However, a good look at the truck's name on the grill will show the shot is backwards. (00:33:50)

Revealing mistake: When the Terminator is in the elevator and the T-1000 forces the door open, the Terminator shoots the T-1000 in the head. If you look closely you can see that the T-1000's head is already split down the middle. (00:59:50)

Revealing mistake: After the T-1000 finishes battering the Terminator with the beam, the Terminator drops to the floor and starts dragging himself. When you see the stump of his left arm move forward then backwards, the string moving the stump is visible. (02:18:15)

Revealing mistake: After the T-1000 steals the truck and throws the driver out there is a big action sequence where the truck hits a lot of cars. In one scene the truck hits 2 cars which were both already stopped across the road front bumper to front bumper, blocking the road in the process, making it impossible for the truck to miss them. (00:33:15)

Revealing mistake: Just before the T-1000 crashes the truck into the bridge and the following shot you can see briefly that it is a dummy in the drivers wheel. The most noticeable difference is the dummy has black hair compared to the T-1000's brown hair. (00:32:55)

Lummie

Revealing mistake: When the T-1000 is chasing John in the transport truck cab, the sparks always appear before the truck actually hits the walls. (02:01:20)

Revealing mistake: In the beginning of the film, when the biker is thrown onto the stove you can clearly see the valves where the steam is coming from - it's NOT from his hands. (00:08:00)

Revealing mistake: In the bar fight scene the Terminator gets stabbed by one of the bikers - if you watch carefully you see the rubber knife bend in one shot. This has been digitally fixed in the 2017 Blu-ray/4K release. (00:08:10)

Revealing mistake: When the two Terminators first fight in the steel mill, in close - up shots the T-1000 is played by Robert Patrick, but in medium shots it's a stunt double who looks nothing like Robert Patrick. (02:13:55)

Revealing mistake: When Arnold begins to beat up and throw around the workers of the hospital, the African American worker is thrown into a window. If you look carefully you can see that the window he is thrown into is a different kind of glass than the other windows that surround it, indicating that this is not real glass. You can also see that none of the other window frames of glass on the inside of the corridor. There is just the metal frames covering the windows. In some shots later in the scene when the T-1000 is chasing them down the corridor you can see the bits of glass that were left over from before have disappeared. (01:01:05)

Revealing mistake: Obvious stunt double for John Connor when he takes a wide berth from the street into the aqueduct. His hair, for example, is no longer across his forehead. (00:34:45)

Daz

Revealing mistake: When the T-1000 is firing out of the hole in the windshield of the chopper, a close up shot shows that there is clear tape around parts of the window keeping all the little bits of glass together. (02:03:15)

Revealing mistake: When the T800 is driving the police car from the hospital, the outside is a clear projection. (01:06:20)

Ssiscool

Revealing mistake: Right after the T-1000 has been terminated and the T-800 is "saying goodbye" you can see the face make-up where you can see his metal endoskeleton bending with facial movement as he speaks. (02:25:00)

Revealing mistake: When Sarah, John and the Terminator drive through the fence to escape the mental hospital, it's (quite) obvious that the T-1000 attached to the back of the car is nothing more than a dummy. (01:05:10)

Revealing mistake: Just when Arnie lifts John onto his bike for the first time, you can see Robert Patrick has been replaced by a stunt driver when he crashes into the wall. (00:37:35)