Continuity mistake: When Sam and Mikaela handcuff all the agents, Sam is wearing a black short-sleeved tee shirt atop a blue long-sleeved tee, before putting on the hoodie. We see the dark tee sticking out when he and Mikaela climb onto Prime. Then moments later, Sam is wearing ONLY a long white short-sleeved (we see it has short sleeves when Bumblebee gives him the All Spark later, through a tear in the hoodie sleeve) tee shirt under his hoodie, when he falls from Prime, when he witnesses Bumblebee's capture and thereafter. (Earlier, after he knocks Mikaela off the moped, from that point on there is a very large hole at the back of his blue and black tees, where we see his skin under the jagged material edges, with no white material seen anywhere. We also see no sign of a long white undershirt at any time when Sam's dark tees go up, during his many action shots.)
Continuity mistake: Odd how Mikaela is not wearing her stud earrings when Sam leaves her to go to Bumblebee and she spots the tow truck across the street, and also when she arrives in the tow truck and says, "Sam, help me with this." Yet, she is wearing them between those shots, when she breaks into the tow truck and hotwires it, and in the prior and following shots.
Continuity mistake: After class when Sam rushes to his father, who is waiting in his car, and tells him that he got an A-, the license plate is affixed to the front bumper. At the start of the next shot, the front license plate is gone, but it then reappears when they arrive at Bobby B's.
Continuity mistake: When Banachek shows Secretary Kellar the photo of Blackout from Qatar, the photo is a photo taken of the transformer in the Beagle 2 video. It's not the photo Epps took of Blackout. You can tell because Blackout has a box-shaped body and the transformer in the photo has a slender body.
Continuity mistake: After Mikaela and Sam walk away from all the handcuffed agents, when we hear an Autobots shout, "Optimus! Incoming!" the railroad crossing post is visible behind the Autobots, but Agent Simmons is not handcuffed to it. Then, when we hear, "Roll out!" Agent Simmons is handcuffed to that post as he should be.
Continuity mistake: When Sam and his parents are being arrested by the Sector 7 officers, inside the house Sam is wearing a blue Strokes t-shirt over a long sleeved shirt. When the shot changes and Sam and his parents are being led in hand cuffs to the police cars, a brown sweatshirt is tucked between Sam's left arm and his back due to the handcuffs. In the next shot, Sam is wearing the brown sweatshirt as he says a line of dialogue. The camera cuts to Agent Simmons of Sector 7, then goes back to Sam, who is now wearing the Strokes shirt and the brown sweatshirt is draped over his left shoulder.
Continuity mistake: During Sam's family genealogy report, when he holds up Captain Witwicky's glasses to show the class, there are cracks in certain areas of both lenses. Those cracks actually change position and characteristics when we see the glasses elsewhere in the film, such as on eBay and when Prime explains their importance to Sam and Mikaela when they first meet.
Continuity mistake: In this movie, we see a close up shot of Mikaela's hands in three separate scenes. The first is a shot from behind Mikaela and Sam where they grasp hands and the camera closes in on that. You see Mikaela's short nails, with chipped red polish. The second time we see her hands is a shot where she covers her open mouth with both of her hands in shock. Her nails are unpolished. Finally, the third time is during the ending sequence where both she and Sam have been thrown to the ground near each other. Mikaela stretches her hand toward him, they touch fingertips, and the red nail polish is back.
Continuity mistake: When Jazz uses his magnetic hand to remove some of the guns from the Sector 7 people, the guns fly into his palm, but in the next shot, his hand is down and there are no guns in his hand or on the ground. He couldn't have put his hand down or thrown the guns away that fast between the shots.
Continuity mistake: After Megatron says to Optimus: ''Then you will die with them!'', Megatron throws Optimus away, and the latter one heavily damages a car, and two others skid sideways in order to brake in time. Two other cars remain parked. But in the shot where Optimus gets back up and draws his gun, only one car remains. Even if the two cars that stopped just before they hit Optimus drove away, there would still be two parked cars and one heavily damaged one.
Continuity mistake: When Optimus is holding Sam and Mikaela during Sector Seven's search for them, Mikaela falls, and in the shot facing up Sam hangs onto Optimus with his right hand and grabs her with his left hand. In the next overhead shot Sam now hangs onto Optimus with his left hand and holds Mikaela with his right hand.
Continuity mistake: When Simmons leads the way into the room with the old Army radio console, he pushes open the massive doors with Keller and the rest behind him (we see the very distinctive wall opposite those doors). When Frenzy pays them a visit at those doors, just as Simmons shouts, "Burn, you little sucker!" in the overhead shot, that side of the doors (in the hallway) is once again visible, only they look completely different now.
Continuity mistake: Just as Mikaela comes to the rescue with the reciprocating saw, when she holds the saw up in front of her face just before she starts to hack away at Frenzy, the saw's blade clamp assembly is about 8-9 inches. After Sam kicks Frenzy, the saw on Mikaela's shoulder has a different configuration with a shorter blade clamp assembly unit. The blade differs as well.
Continuity mistake: Mikaela begins cuffing the undershirt/boxer wearing Agent Simmons arms around a post in the wideshot, then it cuts to the close-up, as she handcuffs the dark suit wearing right wrist of one agent to the dark suit wearing left wrist of another agent. Then in the two following shots we see that she and Sam have actually just cuffed the undressed Agent Simmons left wrist to the dark suit wearing second agent.