Revealing mistake: The final scene is filmed in Brant Rock MA, and the weather is blatantly CGI. If you notice almost everyone is bone dry in a supposed driving rain storm. Look especially at the character perched on top of the submarine tower. For contrast note the "pizza delivery" scene where it is raining heavily and everyone involved is soaking wet.
Revealing mistake: During the police chase with Gabriel on his motorcycle, he stops and turns to start shooting at one of the cops. By appearances, Gabriel is using a standard Glock which had a magazine capacity of 15 rounds. He has no extensions on it at all with the handle and magazine visible. Yet he proceeds to fire the gun 33-35 times at the cop car without reloading and in continuous fire. (00:57:55)
Revealing mistake: During the big shootout on the freeway at the end of the movie, there is a camera pan over all the cars stopped in traffic. There are no people in any of the cars. The shot is so high that you would still be able to see people crouched down if that was the case. (01:56:47)
Revealing mistake: As Will and Ben are wrestling for the gun, it goes off, shooting Ben in the chest. When you hear the shot you can see the gun is lying on Ben's chest with him holding it, and it's pointed pretty much at an exact 90° to his side. It would have barely grazed him at best and would have left a long scratch/cut at that angle. Yet as they get up the shot is perfectly centered on his chest and round as if it was a direct shot. (00:24:55)
Revealing mistake: The teacher has to stop the overzealous Stephanie from signing up to more than one task. Thing is, even before Anna Kendrick grabs the pen from the string, her name is written on the sheet already. (00:03:35)
Revealing mistake: At the beginning of the movie, the protagonists dump the corpse of an agent in the middle of nowhere. The guy is stone cold dead...but you can see the carotid pulse on the right side of his neck, under the fake blood. (00:03:10)
Revealing mistake: After Frank shoots Kevin and Kevin's SUV hits the curb, the background/scenery changes as well as the position of Frank's car. Frank initially pulls along the curb (behind the SUV) with his car at about a 30° angle. The next time Frank's car is shown, it is almost perpendicular to the curb and the Food Mart. When Rupple and Frank have their guns aimed, they would be aiming inside the Mart, not toward Kevin. Objects in the background also change (e.g, fire hydrant, telephone pole appear). (00:16:48)
Revealing mistake: When Bu is packing up his things in his bedroom, the camera appears to sway abruptly from side to side two or three times during the scene, almost as if the cameraman couldn't keep the camera steady. (00:57:25 - 00:57:50)
Revealing mistake: When the bartender recognizes Harold and calls the cartel leader, his phone screen stays on instead of turning black and shows that he's still on the lock screen displaying the time, not actually calling anybody. (00:49:30)
Revealing mistake: During the scenes with the cast on the bridge, there are clear traffic directing cones and lights visible in the distance, depending on the angle. This was done to prevent people and traffic from getting onto the closed set.
Suggested correction: Incorrect. They make a point of showing that there are "Bridge Closed" and construction signs on the bridge, and you can even see some construction equipment on the bridge itself. The cones and lights are not there to prevent people from getting onto set... they're part of the set dressing, since the bridge is meant to be closed down for construction in the scene. That's why they chose the bridge as a meetup point... there will be nobody to interfere.
Revealing mistake: When Paul Castellano is shot, there is a blood spurt shown from where the bullet hits, but the position of the gunman who fires at him doesn't match the direction the blood spurts. The gunman is across the street facing Castellano at an angle, but the blood spurt shown could only be achieved if the two were facing each other directly. (00:56:10)
Revealing mistake: When the agent is questioning Fat Freddy after the cop finds him with coke and a gun, she puts a phone up to his face and says "say cheese." She holds the phone up to his face with the screen facing him. You hear the click and beep of the phone taking a picture, but when she turns the phone around, it's still on the locked screen with just the background and a clock. (01:06:45)
Revealing mistake: When Velma sabotages the science project making it explode into purple goo, you can see that the vial of chemicals she tampered with simply spray around clean liquid, and the purple goo falls from above. (00:23:55)
Revealing mistake: When the Wolf King is arriving through the elevator, there's a shot from a distance featuring Jodie Foster that wheels a chair in. You can see in it that the elevator arrow display is not moving; nobody is using them. (00:50:35)