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, if paused, shows that those cars were both parked across the main road front bumper to front bumper blocking the main road in the process, making it impossible for the truck to miss them.
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: When the T-1000 is chasing John in the transport truck cab, the sparks always appear before the truck actually hits the walls.
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: 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.
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.
Revealing mistake: When the aqueduct chase has finised, and the T-1000 strolls out of the fire, You can see that the semi is hardly burning in the background. Now, 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).
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.
Other mistake: In the bar fight scene the Terminator gets stabbed by one of the bikers - if you put it in slow motion you see the rubber knife bend in a few frames.
Factual error: In the desert when the Terminator uncovers the cache of weapons, they are stored underground in rifle racks without any protection at all. Weapons are normally stored covered in grease, wrapped in cloth or paper and in wooden boxes. Buried unprotected (even in the desert), a weapons cache would turn into rusty junk in a couple of months.
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: When the SWAT van crashes through Cyberdyne's front doors into the lobby, it comes to rest with the rear doors closed. When Sarah and John Connor enter it, it's in a different position and the rear doors are fully open.
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.