Revealing mistake: When SnakeEyes is hanging from underneath the Hummer, the same shot of him turning his head is used twice: the first time just before Scarlett blows the head off of the guy who the Baroness orders to kill SnakeEyes, and the second time just before the train hits the Hummer.
Revealing mistake: When Storm Shadow is stabbed at the end of his fight with Snake Eyes, watch closely as he pulls the blade out before falling. You can see that he has two slices/cuts on his right shoulder. The cut on top is a rather realistic-looking prosthetic, but the cut underneath looks incredibly fake. It's just regular red and purple makeup that was "drawn on" to his shoulder in the shape of a cut and touched up with a small amount of fake-blood. It stands out against all of the other cuts, which are are convincing prosthetic "cuts."