Continuity mistake: When Blackburn is reporting for duty, he asks what it's like. Grimes then puts his hands out, palm down. Camera changes and his fists are now clenched with no time to clench them. (00:11:30)
Other mistake: During Mike Durant's capture the helicopter circling overhead that broadcasts "Mike Durant we won't leave you behind!" is the voice of Tom Sizemore who plays Col. McKnight - it even says so in close captioning." Col. McKnight was in the streets of Mogadishu engaged in battle at that time. (01:44:45)
Factual error: In the movie the first Black Hawk helicopter (Super 6-1) gets shot down and just so happens to crash in a large four-way intersection. In the actual battle, Super 6-1 crashed in a narrow alleyway. (00:49:45)
Suggested correction: many changes were made to factual accounts when converting the book to film. This is simply what has happened here.