Other mistake: The documents to which the Imperial Seal was stamped at both the coronations in Peking (1908) and 'puppet' coronation in Manchuria (1934) carry the same dates. They also show the same 'coronation names' when it is known that Puyi was coronated as 'Xuantong' in Peking and 'Kangde' in Manchuria. This will only be apparent if one can read Chinese. (00:14:45 - 01:47:40)
Other mistake: Ritchie's 1950's Fender guitar amp looks like it would have looked in the 1980's when it should have only been a couple of years old in the movie.