When you reach the Jeep named 'Vera', the engine is running, even though no one could have started it yet.
In the game mode "War", the flags that the Americans must raise have 50 stars on them. However, an American flag during WWII would only have 48 stars on it, since Alaska and Hawaii didn't enter the Union until a few years after the war ended.
The sounds the M1 Garand and Thompson make are not equivalent to the sounds they made in real-life.
In the bonus features menu you can view the weapons used in the game. When viewing these weapons there is a flag in the background indicating the country of origin where it was made. The Lee-Enfield rifle has background showing an American flag, when it was actually made in the United Kingdom.
The Mauser rifle is always in 'safe' mode, with the safety turned to the right. To fire or even turn the bolt, it must be turned to the left.
The Americans use meters for ranging in the game. However, they use yards even today.
After destroying the Black Baron, one of the crewmen of your tank will comment on how it was that tank that drove them from their motherland (Poland). The King Tiger, however, first served in Normandy in 1944 and therefore it would have been impossible for that specific tank to chase them out of Poland. It is possible that they were referring to Richter himself rather than the tank.
In the game, bolt-action rifles can be reloaded whenever the player chooses. In reality, these rifles had to be reloaded in strips of five. It is not impossible for a rifle to be loaded with a few rounds at once; the developers simply omitted having a separate animation to distinguish between loading a rifle with strips and loading with a few rounds, possibly to conserve space or for gameplay purposes.
An in-game use of the perforation 'Boche' is used, only it is misspelled as 'Bosch'.
On the first Polish tank driving mission, one of the objectives lists "Destroy Panzer IV tanks". The tanks on the battlefield are Panzer V Panthers, but once destroyed the objective lists as completed.
The barrels of tank guns can be seen recoiling. Barrels of tank guns do not usually recoil.
In the tank mission you see round bales of hay, however round balers were not commonly used until 1947, five years after the war had ended.
In spite of being held prisoner, the three Marquis members that you rescue in the level named 'Hostage!' are Armed when you find them.