Corrected entry: In the movie, G-man Ned Broy is caught burning incriminating documents and tortured to death by the black-and-tans. However, the real Ned Broy lived well into the 1940s, and went on to become chief of the Dublin Metropolitan Police.
Corrected entry: In the scene where Michael Collins tries to enter the courts, bullet holes are to be seen before any fighting has started.
Corrected entry: It's a well known fact that no one knew what Michael Collins looked like, and, according to the movie, there's only one photograph in his file that shows him more or less from behind. What doesn't fit into this picture is that we see him giving a public speech, watched by British (or British-paid) agents, which was one of many such speeches as Ned Broy later says.