Factual error: When Joseph Gordon-Levitt is playing poker, they are using Morgan style silver dollars. The stacks of dollars are treated as $100 dollars. But a Morgan dollar is 2.4 mm thick, a hundred dollars would be 9 .44 inches high and the stacks of coins were about half of that. (00:11:00 - 00:12:00)
Factual error: Near the end of the helicopter scene Jenko pulls the pin of a grenade with his teeth before he throws it. It is not possible to pull a grenade pin with your teeth as it requires more force than that.
Factual error: After the introduction, there's a scene supposedly happening near Lausanne on the Lake Geneva, but in fact it's altogether the wrong canton, Ticino and most likely Laggio Majore, a couple of hundred kilometers away. (00:06:00)
Factual error: The first kill in the movie - the king who is dead - has rubber soled boots with modern treads.
Factual error: When they torch the car by the docks, supposed to be about 15 years in the past, there is a US Navy Independence-class ship in the background, but the first of these was only launched in 2008, at least 9 years after the scene was supposed to depict. (00:35:00)