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.
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.
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.
Continuity mistake: During the chase scene after the T-1000 commandeers the tow truck, the shadows are inconsistent from shot to shot. Understandable, as each shot was made at different times during the day, but still noticeable.
Continuity mistake: When John Connor holds the Terminator's jacket up to the light in the shed in Mexico it's full of holes. You see the back of it when they leave (to chase Sarah) and there are no holes.
Continuity mistake: As the T-800 is weaving around the back of the semi-truck just before the end of the aqueduct chase, there is a panel of some sort dangling around the back along with the licence plate. From the far shots the licence plate is gone, and the panel is bolted on on. This changes about two times.
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.
Trivia: When the 1000 robot follows them in the helicopter, we can clearly see that he has 3 arms when he is loading his gun with 2 arms and steering with the third. OK, it might be able to generate arms at will, but worth a look...
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.
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.
Other mistake: When the aqueduct chase has finished, and the T-1000 strolls out of the fire, the semi is hardly burning in the background. Considering that the semi has just violently exploded, and the small bridge it just crashed into was nearly flattened, it seems odd that it shouldn't be burning (very tricky to see, best use zoom in).
Continuity mistake: During the aqueduct chase the amount of damage to the semi-trailer truck changes repeatedly. Damage to the semi's grille is severe, then is not. This happens about three times.
Visible crew/equipment: Camera lights are reflected in the glass door in the shot behind Dyson as Sarah Connor laser-scopes him.
Visible crew/equipment: In the Cyberdyne lobby when the Terminator walks towards the SWAT team, you can see unexploded squibs (pyrotechnics) in the wall behind him to his left (before the shooting starts).
Continuity mistake: In the scene where the Terminator and John are at the pay phone John picks the gun off the floor, it's cocked when it's in his hand, but as soon as he passes it to the Terminator, it's not cocked any more.
Visible crew/equipment: In the escape from the hospital where the car is driving fast in reverse, the stunt driver's head is visible sticking up from inside the trunk driving the car from the back. It's too far back to be John Connor's head.
Continuity mistake: In the car chase just before the final encounter in the foundry, the T-800 slams on the SWAT van's brakes and the helicopter slams into it, crushing the choppers front. A second later it is in reasonably good shape.