Continuity mistake: When Kevin goes outside the first time and sees the cars in the garage, the light isn't on. When it shows the garage again in the next shot, the light is on. (00:20:25)
Suggested correction: The light could be motion activated. Either Kevin's movement or passing vehicles could have turned it on, regardless of the time of day. I have motion detector lights in my carport and they constantly go on and off in the daytime if it's low-light and cars pass by fast enough. People walking their dogs can also activate it if they are close enough. They sometimes stay on until I have to manually turn the power off, then on again.
That would explain it only if the light came on when Kevin "activated" it. It stays off during the first scene, and he doesn't make any motion towards the garage when the camera is on him. Nor do we see any vehicles or people pass behind him.
Suggested correction: The two frames are taken from different angles. Notice especially the tree to the right and the two cracks at the bottom. The second picture appears to be slightly closer and lower. The light simply wasn't visible in the first shot.
The two shots are from exactly the same camera position and angle. The screenshot someone provided might have the image cropped differently, but that doesn't mean the camera angle was different.
Revealing mistake: During the sequence with the Native Americans chasing the Delorean in the beginning, in one shot looking up at the sky you can see contrails from a plane, obviously not around in 1885. (00:19:25)
Continuity mistake: The books and other items on the desk of the boy sitting behind Andy move about between shots, and the boys sleeves change from rolled up his arms to pulled down to the wrists too. (00:33:00)
Continuity mistake: When Stuckey hits Vivian she rips his watch off. You can see it fly off to the left. When she bites him it's back on his wrist. Then when Edward pulls him off Vivian it's gone again. (01:00:20)
Continuity mistake: When Henry has just shown De Niro the guns and he returns to his car, you see him light up a cigarette. When the shot changes the cigarette has vanished. (01:54:45)
Visible crew/equipment: When moving into their apartment Patrick Swazye kicks the statue to make it swing so they can get it inside. As they are looking at the statue, two moving men cross in back of them carring a mirror and as they pass you can see the director and camera crew in the reflection.
Continuity mistake: Bruce Willis is emerging from an underground air-vent when the plane with General Esperanza is landing. Initially the plane is coming on a direct course for him and he struggles to get out. In fact the front wheel is on course with and knocks the vent cover. But in the very next scene, the tire marks clearly show the front wheel passed to the right of the vent and so completely missed it. (01:11:40)
Revealing mistake: In the scene where Dr. Ross Jennings is trapped in the corner of the cellar, you can see that the tarantula which starts climbing up his leg has a huge black stick stuck to the back of its body, pushing it along. (01:36:05)
Visible crew/equipment: When Splinter throws Shredder over the wall, Splinter's puppeteer is visible. (Full screen only).
Continuity mistake: When Doug is running from the bad guys after finding out what was going on from his "wife", he tucks his big gun in to his jacket pocket. When he is running through the scanner, that big gun is now in his pants. (00:28:15)
Continuity mistake: When Tracy is tied up in the basement, the rope around his body changes styles between shots.
Continuity mistake: 35 minutes into the film, Cher enters her bedroom with a bowl in her right hand and a bottle in the left. When she gets into bed, both have switched hands.
Continuity mistake: When Kim is watching Edward cut the roses, in closeups she's quite close to the curtain, and it's hanging straight down. In the wide shot she's slightly further away, and the curtain is angled outwards because she's holding it back with her hand.
Visible crew/equipment: Near the beginning of the film when the police car explodes and flips over, you can blatantly see stunt wires used to aid in flipping the car. (00:02:45)
Revealing mistake: The Gremlin who throws the beaker full of acid has his arm operated by a stick, which is visible as he chucks the beaker. (01:08:05)
Visible crew/equipment: Look over Val's right shoulder as Rhonda is supposedly driving upside down with her legs sticking out the back window of the truck cab and you can see a man driving for her. (00:42:40)
Visible crew/equipment: When a carload of bad guys drives past the front of Seagal's sister's house and riddles the front of the house with machine-gun fire, Seagal quickly slams the front door shut, and you can very clearly see all the stunt charges attached to the door.
Visible crew/equipment: When the Red October sub has surfaced to let the crew get off because of the supposed nuclear leak, there is a brief shot where you can clearly see the camera and its filming crew in their tennis shoes on the deck. (01:45:52)
Continuity mistake: When McLeach is using Cody to fish for crocodiles, the hook fastened to the rope around Cody's waist can be seen facing different directions in various shots. (01:06:45 - 01:09:35)
Continuity mistake: The telephone on Scrooge's desk briefly disappears after his maid delivers an invitation to the archaeological society ball. (00:19:05)