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.
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.
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.