Revealing mistake: After Martin cuts his arm off, there are several scenes where you can see the bulge of the actor's real arm under his jacket. This is most noticeable when he is running through the birch wood, and when rooting through the ruins of the burned cabin.
Continuity mistake: It's shown in many scenes that the robot Gallaxar sends isn't particularly quick moving when it walks. But when it's chasing Ginormica around the city, even though Ginormica is sprinting away, it can catch her far more quickly than its speed would allow. It doesn't suddenly speed up - in the shots when the camera focuses on the robot again, you can still see it moving slowly.
Factual error: In the beginning a calendar says 2019 April, you can see April 1 being Tuesday when actually April 1 2019 was a Monday. (00:01:10)
Continuity mistake: When Romey hits the little boy, she immediately parks her car and gets out. She closes the door behind her and runs to the little boy. After making sure he is ok, she goes back to her car and the door is open.
Visible crew/equipment: In the scene with Darth Vader and Oscar the Grouch, watch Darth Vader's eyes. You can see the light screens and crew reflected in his eyes in every shot.
Continuity mistake: When we first see Anna's mom, the bell is on her left hand. But in the scene where Anna is down in the beach house at night and sees her dead mother, the bell changes to her right hand.
Other mistake: When the mayor is talking behind the chainlink fence, with Brent in the background eating sardines, you can see as the mayor grabs the fence, his thumbs clip through the fence wire. This occurs on both hands and easily visible, particularly when Mayor Shelbourne says, "Otherwise, I'm just a tiny mayor of a tiny town full of tiny sardine-sucking knuckle-scrapers." (00:10:52)
Suggested correction: This isn't really what happens, although it looks like it does. The mayor's thumbs are not pointing outwards, they are curled around the fence wire. As he continues to grab the fence, his thumbs don't clip through it, they curl more and more around it, getting a tighter grip on it. Then when Brent says, "But not me, right?", he lets go, and you can see his thumbs curl back out. This is all visible if you look close enough.
Continuity mistake: During the prison fight scene, Silk Spectre's stiletto boot heels are alternatively flat-soled from shot to shot, for the stunt woman's benefit.
Character mistake: When Mr Maddens is talking to the critic at the Mayor's reception, he calls him Alan. The character is actually called Patrick Burns, Alan is the actor's name.
Plot hole: Despite their awareness of the red matter and the power of the singularity, no one on the bridge had the common sense to suggest pulling back to a safe distance. Nero had already refused their assistance so there was no need to stay so close to the singularity. And when a black hole was created inside Vulcan, an officer mentioned they had to reach minimum safe distance, so they know what they need to do, but no-one does it. (01:00:30)
Plot hole: Ben demonstrates for the FBI that he has not only invented gear that allows animals to speak English, but trained ordinary rodents to a level on par with Navy Seals. The FBI laughs at him and cuts his funding, a plot hammer so G-Force can escape and save the day. Are they kidding!?! Even if the info G-force brought back is wrong, Ben has created agents that can repeatedly infiltrate almost literally any place on Earth. No government agency would pass up such a huge intelligence gathering tool.
Other mistake: After Bruno and Lutz had been arrested and are outside the police station arguing, in the background in the left corner, there is a gold Ford Mustang. Then as Lutz is walking away, the same gold Ford Mustang is seen driving in to park in that same place.
Revealing mistake: When the old couple who give Wolverine clothes are first driving towards their house, there is an aerial shot of them driving over a bridge. This is supposed to be set in Canada (drive on the right) but it was filmed in New Zealand (drive on the left). They are driving on the right but the arrow on the road is on the left side.
Factual error: In one scene, focused on a period wood-staked pickup truck parked on the street, you can see clearly a modern Jeep Grand Cherokee parked on the other side of the street.
Continuity mistake: During the other father's song, notice the red record player by the door and the position it's in, with the lid facing Coraline when he says, "making up a song". When the camera angle changes and he says, "she's a doll", the record player's position changes completely, with the lid now facing the wall.
Visible crew/equipment: When Emma goes to crash Liv's wedding ceremony, as she crashes through the glass doors you can see film crew reflected in the glass panes.
Factual error: When the team is running you can see a new model white Range Rover Sport and a red Honda Civic passing by.
Continuity mistake: The first time we see the zoom on the digital watch on Gabriel's arm in the vault, it's counting up the time. Next couple of times we see the watch, it counts down the time. (01:04:35 - 01:05:35)
Factual error: When Robert Bingham is shooting at Cal, an MPD (Washington, DC) squad car shows up. However, the scene is set in Crystal City in Arlington, Virginia, outside of MPD's jurisdiction. Arlington County Police would have responded instead. (01:13:05)
Factual error: In the scene where Tucker is talking with Hugh Hefner, the chess board in the background is set up backwards. The pieces are basic Stanton style, and the kings and queens are obviously in the wrong positions.