In the opening scene, the Berlin Wall on the East German side is shown built right through a cemetery. In fact, by 1965 the East German side of the wall had a 100m "death zone" with barbed wire, mines, and even tank traps to preclude any sort of unauthorized direct access to the wall itself from the east. Likewise, the West German side of the wall also had a "no man's land" that was still East German territory, which allowed the construction of the wall itself, and also gave East German forces the ability to raze buildings and cut down trees that might be used by people on the west side to aid escapees from East Germany, such as the tree shown in this scene. Although people could walk right up to the wall from the western side, they did so at the risk of being shot by East German guards! By 1982, the date shown on the title, none of the wall as shown would have existed any more.
The East German lieutenant in the opening scene is wearing an NCO's belt with a solid buckle (Kastenschloss), whereas officers in all armed services of East Germany wore an open two-pronged buckle.
Also, as he is wearing jackboots, he is wearing the wrong type of pants - all ranks of Warrant Officer (called Fähnrich in East Germany) and up only wore riding breeches in combination with the high boot. Officers could only wear the type of pants shown (Hose lang) with dress shoes or ankle-high boots worn like dress shoes.
The sign on the East German security checkpoint is complete gibberish ("Halt Sicherheit - Nicht ohne Behörde"). Translated correctly back into English, it says "Stop Safety, Not without Office". Most likely, the sign was supposed to say "Stop - Security zone, No entry without proper authority" ("Halt - Sicherheitsbereich, Kein Zutritt für Unbefugte").