Continuity mistake: When Viggo dies, he's sat upright. As the camera changes he's now slouched over. (01:29:25)
Continuity mistake: After the fight with Ms Perkins, John grabs her under her chin and puts his gun to her head. Camera changes to her saying "f**k you" and now his hand is on her ear. (00:57:50)
Continuity mistake: Just after his dinner reservation, we see John driving over a bridge. In the aerial view we can see several cars in front of him on the bridge. However from the shot inside the car, there are no cars in front of him. (00:34:30)
Continuity mistake: John gets his nose broken by Iosef when attacked at home. However, when he buries the dog, there are no marks on his nose or face. (00:14:30)
Continuity mistake: When John is chasing the SUV's at the end, he is level with them, then a distance behind them instantly. (01:23:00)
Continuity mistake: At the start, the blood splatter on John's phone changes instantly between shots. (00:01:50)
Continuity mistake: When John goes on the short rampage with the assault rifle we see one of the henchmen climb into an SUV and floor it. It's clear by the hubcaps and rear of the SUV that it's a Ford Expedition, but the vehicle that hits the SUV into john is a Chevy Tahoe. (01:04:00)
Continuity mistake: When Viggo crashes into John's Charger, it's bent out of shape pretty badly, almost to what would be halfway to the driver's seat. Yet John is fine, and in the next shot, the car is basically too. (01:25:50)
Chosen answer: It was Winston. The guy John met up with in the basement of the hotel who gave John all the information he needed when he was trying to kill Iosef and Viggo.