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. (01:22:00)
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. (01:24:00)
Visible crew/equipment: After the agents are handcuffed, when the Autobots transform into their respective vehicle modes as one of them says, "Roll out!", there are three black ramps positioned in front of the sidewalk, which were not there before. The Autobots use them when driving up onto the sidewalk. (01:24:20)
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. (01:24:20)
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. (01:26:10)
Other mistake: When Optimus picks up the glasses from the edge of the river, his hands are really out of size: the glasses are nearly as big as his thumb, while minutes before, they were big enough to hold two teenagers. (01:29:15)
Visible crew/equipment: Upon arrival at Hoover Dam, just as Sam exits the SUV the reflection of the camera/crane is visible on the vehicle's black surface, at the left, just before it tracks backwards into an overhead shot. (01:34:25)
Continuity mistake: When the SUVs arrive at the Hoover Dam, the lead car pulls up to the curb and the doors open directly in front of the first elevator tower (there are four, which are seen in overhead shots), on its right, with the two Nevada intake towers well ahead of the SUV, on its left. Next close-up, however, as Sam exits the SUV the vehicle is now parked farther up the road, directly in front of the Nevada intake towers to its left and closer to the second elevator tower. Note the yellow pedestrian walkway markings (leading to the Nevada intake towers) the SUV is parked on in the second shot. (01:34:25)
Continuity mistake: As we are hearing Prime explaining, "They're a young species, they have much to learn," we see S-Seven's SUVs pull up to the curb at Hoover Dam and the doors open, right beside the vertical guardrail posts with the horizontal beams. In the next close-up, all of the horizontal beams have vanished. (01:34:25)
Continuity mistake: At Hoover Dam, when the soldiers salute Keller the clock reads 10:00, then as Keller, the soldiers, Maggie and Glen walk away in the background, when Simmons tells Sam that they got off to a bad start the clock reads 11:35, and next shot when Banacheck interrupts it reads 11:43. Also when Simmons talks to Mikaela and Sam the word "Nevada" is gone and it only reads "Time" under the clock. Then when Banacheck says, "Come with me, we'll talk about your car," the word "Nevada" is back under the clock. (01:35:25)
Visible crew/equipment: At Hoover Dam, after the salute, when Defense Secretary Keller speaks with Lennox and Epps, the reflection of the white reflector screen is visible on Keller's glasses. What's more, the boom mic's reflection is actually visible within the reflector screen's reflection. Two for the price of one. (01:35:30)
Continuity mistake: At Hoover Dam, when Sam tells Banacheck the terms of his cooperation (which include expunging Mikaela's juvenile record), Mikaela's high-gloss lip gloss disappears in her close-up, then reappears. (01:36:00)
Visible crew/equipment: After Banacheck walks away with Sam and Mikaela, when Agent Simmons stands by himself on the Hoover Dam intake tower walkway and says, "The man's an extortionist," the reflector screen is reflected in his sunglasses. (01:36:20)
Visible crew/equipment: When Banachek and Simmons are talking to Sam at the entrance of the Hoover Dam, you can see the white lighting panels reflected in their sunglasses. (01:36:30)
Continuity mistake: While standing in front of a frozen Megatron, after Banacheck explains that Sam's great-great-grandfather made one of the greatest discoveries, Sam and Mikaela are shoulder to shoulder, but in the next back shot they are 4-5 feet apart. They're beside each other again in following shots. (01:37:20)
Revealing mistake: When Devastator (the tank-bot) is activated and exits its base through a fence, the upper, obviously-rubber, cannon barrels wiggle around. (01:39:15)
Visible crew/equipment: During the attack on Hoover Dam, after Simmons rejects Sam's request to be brought to Bumblebee, when Simmons tells Lennox to drop his weapon, in the next overhead wideshot the grey tape marker between Lennox's and Simmons's feet is visible, as well as the tape marker at Secretary Keller's feet. (01:43:15)
Audio problem: Before they leave for Mission City, Lennox tells Keller, "Sir, you gotta figure out some way to get word out..." Then in the next shot, as Lennox shouts, "Let's move!" his mouth stays open - not forming the "m" with his lips to produce the word "move", which we hear very clearly (it looks as if he really said, "Let's go!"). Changes in dialogue are done during ADR and often are not in sync with mouth movements seen onscreen. (01:45:45)
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. (01:47:25 - 01:49:15)
Visible crew/equipment: On the way to Mission City, just before Sam spots Optimus Prime, when the camera shows the front of Optimus Prime the camera truck/operator is reflected on the bumper. (01:48:20)
Answer: Primus created the original Thirteen Transformers, later known as the Thirteen Primes, to help him defeat his nemesis, Unicron. The Thirteen Primes were the start of the Cybertronian race, which eventually turned on itself when Megatron, formerly Megatronus, started the War and his Decepticon faction.