At the start of the film when Robert Michaels is trying to kill his double, his double can be seen sticking his arm out from behind the table, but then a split second later the arrow misses his arm and hits him just above his heart. Given the double's body position and the fact that he's turning away from the arrow when it is being fired, it would be physically impossible for the arrow to strike him where it did.
When Sarah is taken to the morgue to observe an autopsy, the medical examiner tells her that the woman died in a motorcycle accident. But the body is completely pristine. Even if she was wearing protective gear, there would be clear physical trauma evident.
At the gas station, even though Sarah pays with USD, the pumps say Diesel, 95E and 98E RON, with 3 separate dispensers which is clearly Western Europe. In the USA the gas would show 87 - 93 AKI and there would be only 2 dispensers, one for diesel and one for all AKIs of gas.
Despite ostensibly taking place in the US, when at Sarah's mother's house, the cars have obviously European license plates.
In the slow-motion fight practice between Sarah and Trent she "stabs" him twice in the lower back. Trent says that the first stab punctured his liver. The liver is higher up in the front. The location where Sarah stabs would be his right kidney.