Continuity mistake: Right before Capazzo dies he holds up the letter, but it's in a zip-lock bag. After the sniper is killed the medic retrieves the soaking wet, unbagged letter.
Suggested correction: The letter is never in any bag, plastic or otherwise. It's always bare or else he wouldn't be worried if there is blood on it. Zip-lock bags weren't invented until the 1950's anyway.
Revealing mistake: When Steamboat Willie shoots a paratrooper running across the bridge who falls off and into the water in the middle right of the bridge you can see a crewmember's right arm in the shot.
Revealing mistake: When Mellish is stabbed, there's already a hole in his shirt before he's stabbed.
Revealing mistake: If you look at the river under the bridge and all other shoots it isn't flowing yet it is quite shallow. In one shot the wind is blowing the surface.The river was purpose built along with the town on former British Aerospace Factory in Hatfield Herts and the river is a shallow oblong mini lake the runs the width of the set.