Plot hole: Where did Cross get the blood on his hands? The gloves were clean of blood after he looked at the teeth and removed the gloves, so where did it come from?
Continuity mistake: Near the end of the film, Violet infiltrates the complex and makes her way into a white room with tons of men in white suits. She starts fighting them and when a couple of guys come at her, she moves quickly and one guy stabs the other in the chest. When she goes to elbow one of the guys in the face, watch his helmet, it comes flying off, revealing his head and hair. When the camera quickly changes to another angle, his helmet is on perfectly straight. (01:17:45)
Revealing mistake: During the motorcycle chase, when Violet is on the building, the chopper gunner badly damages the exterior of the building, with brick and glass particles flying all over the place. But these particles disappear without a trace when they've moved a few feet away from the camera.
Continuity mistake: In the chapel fight, during the first attack, she decapitates a few of Nerva's men, and in the shot of Violet's back, you can see those heads flying through the air. But in the shot from above, all the men still have their heads, and no heads can be seen lying in the middle of the circle.
Revealing mistake: During the fight with the men in white suits, all of these men use swords. Violet disarms a few of them, using then to cut or stab them with. But every time she slices, or better, tries to slice, you can see that the swords never actually cut, but are used as a sort of baseball bat. Also, they are sharp enough to cut someone, because Violet's hands are all cut open at the end of this fight scene. It simply means that these swords are blunt props, and that nobody did anything to make it appear that they are real.
Continuity mistake: When the guard with the customized AR-15 enters the room of the case, there are several guards directly behind him. However, Violet has plenty of time to disarm, kill him, and slowly turn around, upon which the guards reenter the room. It is not possible that they have been shot; the gun wasn't anywhere close to pointing at them.
Continuity mistake: When Violet tries to shoot the guards of the case, we get a close up of Violet pulling the trigger, only to strike an empty chamber. You can see the normal safety pin, and another flat circle. But when she disassembles that same gun moments later, the flat circle has turned into a knob.
Continuity mistake: In the scene where Violet and Six finally make it out of the building, they get into the black car with the door open. When Violet tells Daxis he's full of shit, she puts the car into drive to knock out the men behind her with the door closed. When she's done the door is again open.