Continuity mistake: When XXX arrives at Yorgi's mansion, there are girls in the water fountain out front. If you watch Yorgi's large bodyguard, the one that sports 5 or so earrings and a large beard, you will notice that he takes a girl out of the fountain. A split second later the shot changes onto XXX and in the background the large bodyguard is seen taking the same girl out of the fountain again. (00:54:55)
Continuity mistake: When Yelena and X are on the roof of the building he's staying at and Yelena tells him "Remember what I said, after you kissed me? Never again. I lied.", the shot just before he kisses her she is wearing bright red lipstick, but the next shot it's clearly gone. Likely to spare X from red lipstick all over his face.
Factual error: When Ahab is entering Prague on the river, an aerial shot shows it passing Palackého Square and the Slovanech Cloister, which would mean that it's coming from the South. Yet in the final approach to the bridge when XXX is riding it, it's coming in from the North, with the hill at Letenske Sady in the background. This is all a moot point anyway, since the Vltava river has at least 3 small, man-made falls along its path through Prague, complete with intricate and time-consuming lock systems for river traffic, so unless the Ahab could fly there was no way it could even get anywhere close to town.
Factual error: When XXX is taken to meet Samuel L. Jackson at the Opera in Prague he is driven to the front of the Rudolfinum Concert Hall, yet he meets Jackson at either the National Theatre or the State Opera House (it's definitely one of the two), which are across town. Also, the Rudolfinum doesn't produce operas, they are only a concert venue and have a big pipe organ behind their stage.
Factual error: Near the end when all the police cars (the ones with blue writing as opposed to green) show up at the castle, some of them are 'Mestska Policie' which means city police or district police in Czech. In Prague these policemen are only responsible for keeping the peace, ie handing out tickets, preventing bar fights, etc. They would not have been at such an important and dangerous raid. (01:34:50)
Continuity mistake: When Xander is snowboarding down the mountain to take out the communications tower, he snowboards goofy (right foot in front) to regular (left foot in front) many times. That either means the stuntman is regular footed, or he would have to do a lot of 180's spins, which is impossible to do when there is a giant wave of snow chasing you.
Continuity mistake: When Xander Cage is hung up by his arms in the barn, he is hit by a man with his left hand holding a large knife in his right hand. When the man hits him again it is with his right hand, which should have the knife still in it, but it doesn't. There is no camera shot of the knife at all when the man hits Cage with his right hand, so where did it go? (00:21:00)
Factual error: When agent Shaver shows Xander the bandage explosive for the first time he tells Xander to stand behind the wall then detonates the explosive while he is standing next to it. Agent shaver states that the explosive is powerful enough to blow a hole in a steel safe or vaporize a human. The explosive doesn't appear to be a shape charge, so the explosive force should have gone in all directions and hurt or killed agent Shaver. (00:45:35)jaws65
Plot hole: When Xander is driving onto the bridge, chased by the police cars, we see that there are police cars also blocking the end of the bridge to stop him getting away. How come none of them noticed the ruddy great ramp sitting alone in the middle of the bridge and moved it? It wouldn't take a genius to work out what he might do.