Revealing mistake: When the group are outside talking to Jetfire in the aircraft 'boneyard', on the ground in the bottom right of the screen you can see the tyre tracks where the 3 cars are supposed to pull up to join the shot - then the car on the far right stops and pulls forward again till it's at the end of the tyre track.
Revealing mistake: At the James S. McDonnell Space Hangar, upon finding Jetfire, Wheelie turns and says, "This guy's a legend," and then later Wheelie turns and says, "I tell you, this guy did not age well." These specific CGI frames of Wheelie are the very same frames, and only the background plates (with and without Jetfire) differ.
Revealing mistake: In one of the first scenes with Devastator 'inhaling' everything in sight, there is an SFX shot of some random bystander hanging on for dear life, then losing his grip and being sucked in. During this shot you can see the matte halo around the person as they flail and 'fall'. It is especially noticeable given the general high quality of the effects in the film: by contrast this looks like a cheap effects shot from an old movie.
Revealing mistake: When the battle between Optimus and Megatron first begins, Optimus pulls a dead tree out of the ground, without branches and needles but still standing upright in its basic conical shape, and uses it to beat Megatron. The latter one deflects the attack by pushing it into another tree, the one where Sam in covering behind. When it hits that particular tree, you can see that the end of the tree is perfectly straight, as if it was cut by a saw rather than pulled out of the ground.
Revealing mistake: When Sam is standing on the stairs with his hands up, just before Megatron grabs him and throws him onto the table for the 'Doctor', the rail and balusters in front of Sam have been set up to easily break for the stunt - note the short diagonal bits of wood propped up between them, precisely where they break for the grab.
Revealing mistake: During the battle in Egypt, while Sam is down, there is a slow-motion shot from above with a UH-1 Iroquois (Huey) helicopter flying under the camera. The helicopter is bright white with high-visibility red and yellow stripes, and you can see "White Sands Missile Range" painted on both sides of the body of the chopper in the view from above. It appears to be a UH-1H SAR (Search And Rescue) chopper from White Sands Missile Range in New Mexico: the colors and markings match.
Revealing mistake: When Major Lennox is being sustained by Galloway and Master Sergeant Epps says that he's an "Asssshole!", you can see bunch of soldiers and Autobots in the shot. Sunlight is almost in the middle of the shot; the problem is just the body of the soldiers blocks it. If you watch it closely you can see first a soldier with hat blocks sunlight, after that an Autobot should block it but it doesn't. Again a soldier comes from left to right and blocks it and after that an Autobot should have blocked it, but still you can see the sunlight.
Revealing mistake: After Galloway says: ''You just signed the death warrant on your career major'', we get an exterior shot of the C17 banking sharp to the right, at an angle of nearly 60 degrees. But in the following shot on the inside of the plane, everyone is still standing, and Lennox and Galloway haven't even moved.