After getting shot in the hospital by the fake nurse, Danko and Ridzik are talking while Ridzik is lying on a stretcher. Ridzik asks Danko if they have a shithouse in Russia, and Danko answers, "Yes," without moving his lips.
At the funeral of Danko's partner, the year of death on his tomb stone says 1988. Later on, when Danko checks in at a motel, the date he writes in the book is somewhere in 1987. When Danko is handed the property release form for Rosta at the Chicago Police Department it also lists the date as 1987.
When Danko accuses Streak of lying, Ridzik says he has the right to do so in the U.S. This is incorrect. Lying to a police officer is a crime and someone doing it can be charged with obstructing a peace officer.
When Ridzik attempts to question Rosta about the key, Rosta says in Russian (according to Danko) "Go and kiss your mother's behind". However, Ridzik tells Gallagher that Rosta told him to f-ck his mother's behind.
The teleprinter at the Moscow militia headquarters is seen printing a message in Russian but in the Latin alphabet. Equipment used by the Soviet government would undoubtedly allow the Cyrillic alphabet to be used.
At the beginning of the film where they chase the villain he jumps down from a roof and there can be seen several dumpsters. Those were not the kind of dumpsters used in Russia. Those were of western design.
In the article by Fowler in the London Times there is the word "kilometers" with the American spelling rather than the British spelling "kilometres". It is very unlikely that an article by a British journalist in a British newspaper would use this spelling. It is also unlikely a British newspaper would use Kilometres, as Britain still uses imperial miles, road signs, speed limits etc are all still stated in Miles. Although for smaller measurements, the metric system is used, Kilo's instead of Pounds and Centimetres in place of inches.
The Russian letters that appear in the opening credits are all used in the wrong context and don't make sense phonetically. For example, the Russian letter resembling an inverted R is actually pronounced as "ya"; the Russian letter resembling an inverted N is equivalent to I in the Latin alphabet; and so forth.
After the cross dressing nurse shoots the air bubble into the Russian man in the hospital, the man supposed to dead. But the next screen shot of the two you can see the dead man is moving his head side to side.