I don't care about the inaccuracies, as long as the movie is good. The trailer to this looks horrible.

No film is "non fiction". I'm always amazed at people who really get angry at feature films for getting facts wrong. It's show business. Duh. The tropes used to attract audiences will always have priority over historical accuracy.

For instance, supporting actors are always shorter than the person they're based on, to make the lead actor look taller. Tommy DeSimone was about 5 feet taller than Henry Hill.... Not in the movie he wasn't.

Lefty Ruggiero is killed in the movie. Because it's sadder that way, that's why. The audience felt sorry for him. Nobody would have cared if Sonny Black died, which is what really happened, because Michael Madsen was calculated and emotionless throughout the whole damned movie.

Even adaptations deviate from the books they're based on. Fredo Corleone wasn't a complete moron in the Godfather book. He was just dependent on his parents, less willing to take risks and branch out, which made him a weak candidate to take over the Corleone clan. In the movie, he's made to look like a doofus....to make Al Pacino look cooler. It's that simple.