Continuity mistake: At the very beginning of the film when we see the garbage man picking up the steel bin with his forks, if you watch closely you can see the shadow of the large forks pass the windscreen, yet in the following shots the forks are lower than the windscreen. (00:03:50)
Audio problem: When the Terminator first arrives in 1984, the whole time displacement sequence (or whatever you want to call it) is witnessed by a garbage truck driver who mutters 'What the hell?'. His mouth however is obviously saying something else which has been dubbed over. (00:04:00)
Visible crew/equipment: After the Terminator arrives in 1984, he begins to walk over to a short concrete wall and looks at Los Angeles over it. A second before the shot ends, the shadow of a camera is visible to the left of screen. (00:05:05)
Audio problem: Early in the film, when the punks are at the park, one of them is looking through a telescope and the other one breaks an alcohol bottle over it and says "Hey, it's my turn." If we look more closely, he actually says "My fu***ing turn." (00:05:10)

Continuity mistake: At the start of the film when we first see Reese arriving, the drunk homeless guy is holding a bottle in his left hand, then the camera continuously switches between Reese's arrival and the old guy, in these shots, the bottle keeps changing hands from left to right, then back to left. (00:06:40)
Audio problem: When the terminator smashes the car window, the crash sound occurs before his fist actually makes contact. (00:12:35)

Continuity mistake: When the Terminator punches through the car window, there's broken glass all around the window frame. When he closes the door, there's only a little glass around the top of the frame. (00:12:55)

Character mistake: When the Terminator walks into the gun store, the "Clearance" sign in the window is misspelled "Clearnce." (00:13:40)

Revealing mistake: In the second 'future war' sequence where a female soldier is practically vaporised by a passing HK tank, watch her flaming remains. You can see the (exceptionally fake looking) head of the stand-in dummy tumble away from the body. (00:14:15)

Continuity mistake: Arnold looks up Sarah Connor's address in the telephone book. The telephone book address has 4 digits, but he goes to a house that has 5 digits on it. (00:15:00)

Continuity mistake: When the Terminator steps into the house to kill Sarah Connor he walks over the thresh-hold however in the next shot he is outside again. (00:16:15)

Revealing mistake: The second future war segment: During the wide shot where Kyle and the female soldier are following the HK Tank, most of the plasma shots fired from said tank seem to come from above the gun turrets and not out of the barrels. (00:18:45)
Revealing mistake: In the second future war sequence. At the end of the HK/car chase, the gunner in the car has been replaced by a very obvious dummy. (00:19:55)
Continuity mistake: Kyle loads a shell into his shotgun then falls asleep and dreams of his past in the future. When he wakes up he pumps the shotgun, so the first shell should come out, but doesn't. (00:20:05)

Continuity mistake: Early in the movie, prior to heading out to the bar where she first sees the Terminator, Sarah Connor is holding her iguana at her apartment while talking to her roommate. In the first shot, she is holding it with her left hand under the lizard's chest. The film cuts to a different angle, and now the lizard is resting against her shoulder, with Sarah's left hand on its upper back. It cuts back to the original angle and again her hand is supporting the chest. (00:23:25)
Continuity mistake: The telephone message left by Sarah's roommate changes the two times we hear it. The second time, there is no delay between "Hi there" and "ha ha ha fooled you", while the first time has a delay of over a second. (00:25:55 - 00:32:05)
Continuity mistake: When Ginger is rooting through the fridge while her boyfriend fends off The Terminator in the bedroom, Pugsley the iguana scares her by knocking some food off the top of the fridge. We then see a close up shot of Pugsley knocking some more food over. In this shot we see him knock over a box of "Harvest Wheats" onto its front and a box of "Honey Grahams" placed on its side and at an angle. We then cut back to Ginger telling him to shoo and then back to Pugsley. In this second shot, the box of "Honey Grahams" is now standing upright and facing the camera and the box of "Harvest Wheats" has completely disappeared. (00:30:40)
Continuity mistake: When Sarah is sitting in the bar after talking with the police, there is a drink in a glass on the table in front of her. The scene cuts away and when it cuts back, it is a small bottle, not a drink glass. (00:33:45)
Suggested correction: When she sits down, there's two empty mugs and two bottles, but she doesn't have her own drink. The scene cuts to the Terminator coming in, and then we see her with her drink (a bottle and the glass). But enough time for someone to bring it to her.
Continuity mistake: In the Tech-Noir bar scene, as Sarah is seated at the table and knocks the Canada Dry bottle to the floor, right when she leans down to pick it up, a guy sporting a white suit, white tie with three black tie clips and red pants begins passing behind her from the right side of the screen. In that exact same moment, while she's still bent over retrieving the bottle, the reverse-angle shot captures that same guy in white suit and tie, now dancing in front of her table as Arnold walks up scanning the area. (00:34:20)

Continuity mistake: In the Tech Noir Bar, the same woman - blonde with a pink or orange dress - must have come dancing with her twin, because while she's sitting behind Sarah Connor when the laser beam is pointed at her, she's also dancing near Arnie. The T-800 moves past her when he sees Sarah Connor and moves to shoot her. (00:35:05)