Revealing mistake: When Connor and Cameron are trying to save Derek Reese from the police truck, Cameron walks on the Jeep's hood to jump onto the police truck. During her walk, we can see that it isn't Cameron but a stunt double. She doesn't look like Cameron and is a bit taller.
Continuity mistake: Ep. "Samson and Delilah" - When the Jeep Cherokee flips, it lands on the driver-side/rear corner of its roof, completely collapsing that corner of the roof. The camera angle changes and instantly the Jeep is landing on both of its driver-side tires, roof intact, and rolls onto its left side. The angle changes again, and the collapsed roof is back as the Jeep slides a bit more before the shot changes again, and the undamaged roof is shown as the Jeep rolls onto its roof and comes to a stop. The camera pans around the rear of the wreck, and there is no roof collapse at either rear corner.
Deliberate mistake: On several occasions throughout both series/seasons, whenever a Terminator fires a weapon, they blink. This should not happen because that would be a human reaction - Terminators aren't human. They're made to look and act human, but SkyNet don't focus on the little things; such as emotions, breathing and reflexes. The three most notable instances of this are in Season 1, Episode 5: "Queen's Gambit", Season 2, Episode 21: "Adam Raised a Cain" and Season 2, Episode 22: "Born to Run". In "Queen's Gambit", Cameron blinks as she fires a machine gun at the T-888 in the back of the black van as he runs towards her, in "Adam Raised a Cain" the water delivery Terminator blinks as he shoots Savannah Weaver's nanny Debbie and as he shoots the security guard and Catherine Weaver in "Born To Run".
Continuity mistake: Ep. "Samson and Delilah" - As Derek sits at the table, Sarah is digging jelly from a jar with a knife, moving it onto toast that sits on a plate on the table. The shot instantly reverses and the jar is on the table and she's spreading the jelly with the knife on the toast she now holds in her hand.
Continuity mistake: Ep. "Samson and Delilah" - Sarah carries a plate with a sandwich and a tall glass of milk for John. After talking with Cameron for a few moments, she heads to John's room, arriving with the plate and sandwich, but no glass of milk, and with some of his clean clothing.
Continuity mistake: Ep. "Samson and Delilah" - When Elison is sitting at the rear doorway of the ambulance, in close-up his hands are away from his face, out of shot. But the instant the shot changes to show him from further away, his right hand is covering his mouth.
Continuity mistake: Season 2, episode 21, "Adam Raised a Cain." While in the garage of Ms. Weaver's house, a terminator, out to get Savannah, takes four bullets from Sarah in the back. Later as you see the terminator go after John and Savannah, you can see his back as he is coming up some stairs, and the terminator now has five bullets holes in its back.
Revealing mistake: "Season 2, Episode 20: To the Lighthouse." When Cameron is firing back at the man on the passenger side of the van coming at her, the man drops the gun in his lap when Cameron shoots him. The very next shot shows the gun tumbling around on the road on the opposite side of where he was shooting.
Continuity mistake: EP "Goodbye to All That": On the firing range when John Connor fixes the stoppage on the rifle, his shooting glasses are on his head, when he hands the rifle back, the glasses are now over his eyes, and in the next shot they are on his head again. Not enough time has occurred between shots for this to happen.
Revealing mistake: Ep. "Samson and Delilah" - As Cameron flips over the Jeep Cherokee, the smoke coming from the bottom of it is from the cannon used to flip it, the cannon in later shots then disappears, more notably when the camera goes above the Jeep with Sarah crawling out.