Visible crew/equipment: After the T-1000, disguised as Janelle, impales Todd, it hangs up the phone and pulls the blade out of Todd's head. As he slumps forward away from the cupboard and drops out of frame, you can see the retracting-blade rig that was attached to the right side of his head, creating the illusion that the blade was pulled through his head. Frame-by-frame helps on this one - it's visible for the last 3 frames before he disappears, just past his chin. (00:41:25)
Continuity mistake: When the Terminator pulls John off the dirt bike during the drainage ditch chase, the dirt bike falls onto its left side and the gas tank is about to be crushed by the tow truck. The next shot from another angle shows the dirt bike laying on its right side, with the rear tire the first thing to be crushed under the truck. (00:37:30)
Continuity mistake: When Sarah Connor hits the guy with the broom handle in a bid to escape, after the first hit, we see a close-up shot of him on the ground clutching his face. In the background we see her swing back and start bringing it down again. We then cut to a wider shot, and she repeats the motion. (00:52:40)
Revealing mistake: In the scene where Sarah opens the skin and endo skull of the Terminator, you have a shot where you see the reflection of the Terminator, Sarah and John in the mirror. When the camera takes a shot from the back of the Terminator, you see the back of a puppet on which the real Sarah is performing the operation. In the reflection you see no camera, the real Terminator, and doubles of Sarah and John. Especially the moment Sarah puts down the screw driver, the reflecting screw driver is put down a fraction later than Sarah's. (01:07:09)
Continuity mistake: When the T-800 and Connors are leaving the hospital in the car driving backwards, the car jumps off a grassy embankment and lands hard on the asphalt, knocking the rear bumper loose to a hanging position. A few shots later the bumper is back on snug again. (01:04:50)
Continuity mistake: When the T-1000 walks through the bars at the mental clinic, he gets his handgun stuck in the bars for a few seconds before removing it. In the close-up shot we can see the gun is stuck. But in the wide shot that precedes it, his gun isn't stuck at all. Actor Robert Patrick (T-1000) unconvincingly has his arm wrapped around the bar to make it look like his gun is stuck. (01:02:00)
Revealing mistake: Special Edition. The biggest giveaway about the false mirror in the 'chip removal' scene is that John's 'reflection' has his back to the mirror when Sarah is drilling, whereas the real John is standing side-on to it. Also notice that John nervously looks at the camera in this shot. (01:11:50)
Other mistake: Repeated footage of a car crashing is used during the chopper/SWAT van chase. The clip is first seen just before the onset of the shootout between Sarah and the T-1000. The same clip is shown a second time as the two vehicles are about to pass up the nitrogen truck just before the chopper flies over a pedestrian bridge.