Continuity mistake: When John and Cassian see each other through the fountain, they start to shoot at each other when the water comes back up. You hear the civilians around them start to scream and panic, but when the next shot cuts to John shooting through the water, the civilians are walking casually around calmly as if nothing is going on, but then in the next shot they are all running frantically. (01:17:45)
Continuity mistake: John shoots Santino once and gun slide locks open, showing gun as empty. In scene prior, John specifically checks gun and pats down Ruby Rose to get a fresh mag (and pockets a second) before heading to Continental.
Character mistake: Once Santino and Ares find John again in the hall of mirrors, John is fighting two of the grunt men that came in with Ares and kills them. Both of which had light assault rifles and weapons on them. John and Ares proceed to empty their pistols out at each other before she runs off with Santino. John then throws his empty pistol away and gets up to pursue his target unarmed and while limping. It is unreasonable to think that someone with his skill and training and experience would not take two seconds to reach down and pick up one of the guns dropped by the two men he just killed before chasing after his target, especially given the highly trained body guard with him accompanying his target. As well as probable encounters with more grunts. To add to this, he was seen doing just this moments before when he had limited ammo and each time he'd down a few enemies he would pick up one of their guns and continue. (01:41:30)
Continuity mistake: On the subway during the fight between John and Cassian the other travellers in the background constantly change in both position and number, sometimes there are 2 sometimes there are 4, and although they are seated their seated position changes between shots. (01:21:20)
Revealing mistake: In the beginning of the movie, when John get his Mustang, he starts accelerating deliberately to hit one of the cars (black sedan), but right after the odometer scene (where you see the gas going up) you actually see the car is stopped. It is pretty obvious. (00:09:30)
Continuity mistake: On the subway while John and Cassian eyeball each other, from the front there's no-one in front of Cassian, just a guy in a hat off to the side. But from the back, another man appears between them.
Suggested correction: You can see the edge of that guy cut off on the edge of the shot he is there, that grey hair and that same jacket.
Continuity mistake: When John gets out of his car at the very start, he is on a zebra crossing. When he gets back in, the car is no longer on the crossing. It's hard to tell, but the car has moved. (00:02:00)
Suggested correction: The car is still on a zebra crossing, when John gets back in. Stripes are very obvious.
Continuity mistake: The damage to the car after it gets smashed in the beginning the damage to the car is different to when he pulls into the driveway. (You can really notice when looking at the damage to the headlights in particular).
Audio problem: When John and another bodyguard/hitman are walking in a crowded subway/train station, and they're shooting at each other with suppressed 9mm or 45 ACP handguns across swaths of people and the people not reacting is an absurdity. High caliber handguns meaning anything larger than a .22 still makes a loud noise when suppressed. People in a general vicinity could still hear a noise and a pop. The only truly silent handgun is a .22 and it still makes a noise when the slide reciprocates back and forth. (01:18:00 - 01:18:45)
Continuity mistake: Before John starts to shoot Cassian by the fountain the blood on his left cheek increases and also the wound on that side gets smaller.
Continuity mistake: The amount of blood on John's right ab decreases when he is in the subway after the violin girl shot him.
Continuity mistake: When John enters the Continental with his dog, there is a female bellhop starts walking behind him. However she disappears instantly. (00:26:50)
Continuity mistake: When Santino says he's sorry about John's wife, he's looking at one photo that has got a sparkly frame. When the camera changes, the frame is now wood effect. (00:20:20)
Continuity mistake: Just before John shoots the Russian in his kneecaps, he is thrown flat on the floor. When the camera changes he is sat up. (00:11:40)
Continuity mistake: When John is fighting the gang men at the start we see him crouching over the unconscious body of a thug. John then looks up and dives out the way of the speeding car, however the unconscious thug has disappeared when the taxi hits John's car. (00:11:50)
Continuity mistake: The damage to John's car at the start is constantly changing. For example, he reverses into a car and smashes the rear of his car up. A few seconds later it's in perfect condition. (00:09:00)
Continuity mistake: When John arrives at the Continental, we have an overhead shot showing two doormen to John's left. Camera changes to behind John and now those two doormen are suddenly talking to someone in a blue suit. (00:26:50)
Continuity mistake: When Santino places the metal item on the table after saying John will always be that man, there is a white item on the table next to it. As John pushes it away, the white item has disappeared. (00:22:40)
Continuity mistake: After the motorcyclist crashes into John's car, in the wider shot all John's headlights are on, then as he gets out, all but one are off. (00:02:15)
Deliberate mistake: One of the bodyguard's rifle which is a Sig model SG553 only has a front sight and no rear sight. The rear sight can easily be attached to the Picatinny rail. Such a rifle is only good for up close instinctive shooting, anything at distance is spray and pray. (01:39:00)