If the Player loads the rifle before he has fired all the rounds in the magazine, the reloading animation is still of 5 rounds being loaded in irregardless of how many rounds have been fired.
The Browning .50 caliber heavy machine gun is not capable of firing as fast as it is depicted as doing.
The trajectory of the gun on the Coast Guard cutter is too high for a naval gun.
There is a fan in the sewer that the Player must bypass. Because flooding in the sewer would naturally compromise the fan, such fans are typically placed close to the surface rather than right by the water.
When the Player fires upon hostile NPCs, they call out, but do not seem to react to his presence.
The gun on the Coast Guard cutter does not have clearance enough to fire past the bow of the ship.
The maximum amount of ammunition carried should be a multiple of the maximum amount of ammunition carried in each magazine.
The game is set in 1922, but features the Federal Bureau of Investigation. The FBI was not under that name (at the time of the game it would still be called the Bureau of Investigation), and did not use the seal featured in the game until 1935.
In Hogg's office there is a crate blocking the only door to the room. There is no way that it could have gotten there if the last person to have used the room left by the door.
When Mr. Marsh captures Mr. Walters, he does not remove his inventory.
It is unlikely in the extreme that Federal agents would be allowed to demolish an entire foundry, especially given that it contains vast amounts of gold.
When talking to Ms. Lawrence, Mr. Walters refers to Mr. Waite as 'Waites'.
U.S. Marines are calling NCOs 'Sir', an honorific typically reserved for officers.