Revealing mistake: In one of the opening scenes the platoon of the captain is gunned down by a MG42. You can see the crimped fronts of the blanks in the belt.
Revealing mistake: At the very beginning of the movie when Billy is getting his hands wrapped as Eli is taping his right glove, part of the H in his fighter tattoo has been rubbed off from when his arm was resting on the chair while they wrapped his hands. (00:02:40)
Revealing mistake: In the shot where Laing hears the horse neigh, at the top right corner of the screen that there are trees on the other side of the wall, where only the blue sky was before. (00:19:15)
Revealing mistake: When the Nazi doctor starts to torture Solo in the electric chair, he turns off all lights in the room except for a single dim light bulb over Solo's head; so, we know that the background is uniformly dark. Moments later, when Ilya comes to the rescue, a lighted control room appears behind the doctor, off to one side. After they strap the Nazi doctor into the electric chair, there is now a lighted control room directly behind the chair.
Revealing mistake: When Verdean is scrolling the Wikipedia page for the Israeli wrestler "Johnny Jerusalem", the page itself is a well thought out fake one (the wrestler in question is non-existent), but the prop person who made this fake did not bother going all the way through editing the wording of the footnotes ("References" paragraph), that display instead the name of the real wiki page they edited as foundation. The webpage is an edit of the real Wikipedia page of The French Angel, the real life pro-wrestler who was also rumored to be an inspiration for the look of cartoon orc Shrek. All the names and dates have been slightly altered ("Paul Blowzier in New York" instead of Paul Bowser in Boston, "Carl Pohiello" instead of Karl Pojello, etc). (00:37:20)
Revealing mistake: The idea is that the characters are in some super remote area where there are no working phones and nowhere to get help, but throughout the movie you can see a town in the background with buildings.