Other mistake: After Xander escapes the avalanche by grabbing the pole, the avalanche is suddenly over. If it was that big of a avalanche it would have gone a lot farther.
Other mistake: The shot of the windows falling off when agent Milan Sova touches them is repeated, it's like they are coming down a second time and not in a dramatic "replay" sort of way. Also, if the windows come down, in unison, when a guy simply taps the glass to wipe a bit of dirt off (he was not leaning on it with his body or he would have fallen as well), the building is made of playing cards, and we have seen snow in the previous scenes, which would have built more pressure on those roof windows than that guy's hand, tenfold. (00:48:15)
Other mistake: When the bad guys take the cop from the bar, he starts talking to them in English and everyone is, for no reason since they are in a bar in Prague they own and he is from the local police force. In the rest of the movie it is otherwise abundantly shown when people speak a foreign language, but for that scene it wouldn't have worked. (00:35:55)
Other mistake: Tony Hawk's crew recovers in a handful of seconds the three cameras that recorded Xander Cage's insane stunt. Considering it's 2 guys wearing sleeveless tank tops and one camera was strapped to the hood of the car (and the car fell hood-first, right on top of it) and the other was secured inside the burning car itself, you gotta wish someone filmed THAT operation, because sounds xtreme as hell. (00:09:10)
Other mistake: Coming out of the same door he went through at the beginning of his dungeon quest, Xander shoves back the guy he stunned; considering the sedative is supposed to last for 12 hours, what is he doing standing there? But if we assume that sedation in movies does not matter and you can just wake someone up with a slap on the cheek, fine; there's still a continuity mistake when we consider that Xander pushes him back quite far but when the two henchmen come out of the door they find him much closer. (01:19:20)
Other mistake: The bad guy spots Xander snowboarding using telescope. The telescope's angle was too low to spot him as high up on the mountainside as he actually was at the time. You can see how far down the building is as he pauses to trigger the avalanche. Keep in mind that he was in fact higher up as he was spotted before triggering the avalanche.