Other mistake: When the Terminator blows his way into the lab, Dyson stops Sarah from going on, saying "the fire's set off the halon system," referring to the gas which starves the fire of oxygen. However, the subtitles on the DVD say "the fire's set off the halo system." (01:43:20)
Continuity mistake: When the T-800 is walking down the corridor at Dyson's workplace, how far he is down the hall keeps changing depending on the shot. (01:38:40)
Continuity mistake: In the Pescadero hallway, the T-1000 passes by Dr. Silberman twice, the second time while firing his pistol.
Revealing mistake: After the Terminator has jumped on to the truck and shot the T-1000 full of bullets he pulls the wheel to the right so that the tanker truck skids and falls but if you look closely you can see that the stunt double for the T-101 merely fakes he's pulling the wheel, and then holds onto the cab and you can see the stuntman for the T-1000 inside the cab turning the wheel before it flicks to the wider shot. (01:48:10)
Revealing mistake: Before the Terminator is lowered into the steel, he says "goodbye." You can see his breath revealing the actual temperature on the set.
Revealing mistake: When the truck chase scene ends with a wheel moving in flames, Terminator and John leave on the bike leaving skid marks on the road. Watch the left side and you'll notice another skid mark from a previous take.
Visible crew/equipment: When the Terminator looks back and fires his shotgun at the truck's tire, on the far right side we can see part of an orange cable or pole with rigging attached to the back of the motorcycle. (00:37:40)
Visible crew/equipment: When the T-1000 is chasing John, the terminator, and Sarah in the cop car, the terminator backs the cop car off the ramp, making the car bounce around. At the very end of this shot, you can see crew members, light equipment, and camera dollies put off to the side.
Revealing mistake: At the guard hut, when the Terminator goes to smash through the window you can see the different colored area and the line where the glass breaks.
Continuity mistake: At Cyberdine, Gibbons' chair position differs between the shot when the second guard arrives and after he finds him laying on the floor.
Continuity mistake: While in the police car, escaping from the T-1000, when Sarah says "John, it was stupid of you to go there", her ponytail is either brushed and neat, or messy and all over her shoulder, depending on whether the shot is from behind or the front respectively.
Continuity mistake: When the T-1000 is shot down next to the video games arcade, his face expression changes between frames. (00:32:25)
Continuity mistake: When the T-1000 throws the driver off the truck and chases John's bike, the buildings on the right are a brown parking lot and a modern white building. In a couple seconds, the truck keeps swapping from being by the middle of the white building or way behind, next to the brown parking lot approaching the white building. The position is inconsistent many times.
Continuity mistake: Arnie shoots the truck's tyre right before it smashes against the pillar. From the truck's point of view Arnie and the kid disappear, only to reappear one second afterwards.
Revealing mistake: In the scene when the T-800 first comes through the time machine, in the shot where he stands up. If you look towards the right side of the bowl shape that's melted into the ground, you can see that the bowl shape is actually above ground. There's a shadow being cast by it on the right side. (00:06:30)
Character mistake: In the alternate ending on the DVD edition Sarah says that Michael Jackson turned 40 on the supposed day of the war. Michael Jackson's birthday is August 29 1958, so he would have been 39.
Continuity mistake: The T-1000 has the gun holster on his left side and takes the gun out with his left hand when the guard in the psych ward hits the alarm. A few scenes later when the T-800 (Arnie) asks Sarah to 'come with me if you want to live' the T-1000 walks through the cell doors, the holster is on the right hand side and the gun in his right hand. (01:10:00 - 01:12:00)
Suggested correction: The T-1000 can change shape at will so it is safe to say the he changed hands with the gun and switched its holster to suit. The T-1000 uses both hands throughout the film to hold and shoot his gun.
I am not sure if the holster has changed to his right-hand side at all - isn't that just his walkie-talkie, which was there all along? Very few clear shots of his belt in that sequence though. I hate speculative explanations but if it's just the gun changing hands, that doesn't sound too serious... Could just be for opening a door.
Continuity mistake: After the first fight in the steel mill, as the T-800's arm ends up in the gear the black glove on his left hand is torn in many places, revealing parts of the endo-skeleton hand. However, later when the T-800 frees himself from the gear, he is wearing a black glove with no tears on his left hand.
Visible crew/equipment: When The Terminator exits the bar, a bartender then points a 30-30 at him. The Terminator then takes the 30-30 off him and takes a pair of sunglasses out of his shirt pocket. A reflector screen is visible in the reflection of the glasses when he puts them on. (00:10:10)
Continuity mistake: When the cop by the vending machine is killed, his head is tilted to the left in the front shot, but straight in the side angle following.