Revealing mistake: When the Sergeant has the shotguns in the backpack on his back, and you see a close up of his face, you can see that the shotguns do not have triggers. On plastic prop rifles, the trigger is usually molded into the trigger guard in the pulled back position, and you can see this on these prop shotguns.
Revealing mistake: When the C130 is taxing on the runway (just ahead of the police search of the plane) you can see a C-17 in the background. The C-17 only made its maiden flight in 1991.
Revealing mistake: When Art is hitting the Trevor (the blinded man) character with the hammer/hatchet in the beginning, if you look closely, you can see blood coming from Trevor's head, yet there is no wound or cut. The blood is actually coming from the prop that is hitting him in the head. (00:09:00)
Revealing mistake: When they blow up the whale, it is obvious it is just a large prop, as there isn't much blood or tissue flying through the air. You can tell by comparing it to the famous news reel online that shows what happened when the exact same thing happened in real life.
Revealing mistake: In the jazz club, the saxophone player's finger movements don't match what he is playing.
Revealing mistake: When Joseph goes to pick up the prisoner, there's a close-up of the paperwork; the prop is something recycled, or perhaps a real prison movement slip with Alex Veadov's picture stapled on, because the character's name is Vadim Nezhinski, a white Russian, but the documents say "Anderson, Robert", with a B (Black) for race. (01:09:45)
Revealing mistake: After "Do you want to die with dignity" all hitmen drop their magazines of blanks.