Continuity mistake: Kaiser-Friedrich Museum: In the building where you find the Mosin, there is a window directly over the truck on the next floor. By that window is some luggage. If you look directly at the corner while standing by the luggage, there is no light on the ground by the luggage. But if you turn Karl slightly to the left to look at the wall where the window is, suddenly light appears on the floor in front of the luggage coming through the window.
Continuity mistake: Kaiser-Friedrich Museum: At the door way of the first checkpoint, if you turn around and look at the wall next to the window standing more towards the wall on the left, you see light on the wall in a small spot that is in front of you by the other doorway. If you move Karl over just a little bit to the right, the light disappears on the wall. And it is not Karl blocking the light.
Audio problem: Kaiser-Friedrich Museum: In the building where you find the Mosin Nagant Sniper Rifle, you pass by a door way that is blocked by a truck as you go up stairs. The truck is running, and even while idling, it is a very loud old WWII era engine. You go upstairs and into the next room, after fighting the three guys up there, you grab the Mosin. When you do, a cut scene starts as Karl talks about the weapon he just found, and then goes back to where you control him. Return down stairs and now the truck is gone, the door way able to be walked through. However, at no point did you ever hear the truck leave. Grabbing the weapon is what triggers the cut scene and that is when the truck leaves, yet despite being by a window right above the truck, not once is it ever heard.
Other mistake: Kaiser-Friedrich Museum: At the beginning on the bridge you see several Russian soldiers. The ones just walking idly about on the bridge seem to be blind idiots. They just run into things causing collision and so, they just stand there walking in place against obstacle. Sometimes they turn a bit and keep walking until they hit the next obstacle.