Diehard fan, thought it was between poor and terrible. I can't tell you the last prequel/sequel I saw that was 5-15 years later that was good, but I had faith with Chase.
Virtually every character (who was based directly on someone from the show) felt massively overacted with the exception of Livia, who knocked it out of the park IMO (could have used more hand gestures.) Johnny Boy non existent in the movie, and when he was, there you got cheese ball lines like "all I wanna do is bang my goomah and take a nap." Sil and Paulie felt like they were trying too hard. Dickie looked/sounded and felt more like a young Richie Aprile imo. Liotta's characters were both blah and fairly pointless, with Uncle Sal as someone stated above merely serving as a Melfi-lite for the movie.
Zero development of the relationship between the Sopranos and Dickie and as to WHY the entire family, Livia included, apparently worshipped the guy. Meanwhile the entire plot line focuses on Dickie, yet not much is accomplished other than him taking out a few people very close to him. The Harold plot line seemed forced, and never given a proper backstory.
Continuity wise - I don't understand "the twist" at the end. In the series, so much of Chris' loyalty to and love for Tony is centered on what Tony did for him - i.e. give him the man who killed Dickie. Why change that entirely for the movie as if this never happened in the series? The movie literally ends with Chris saying "that's the man I went to hell for" which is a direct reference to Chris saying he would go to hell for Tony for allowing him to exact revenge on his father's killer in the series. But yea.....let's make Jun responsible instead because Hollywood.
Also, how are Sil and #### completely established soldiers the entire movie - yet during the series, they're all roughly the same age with daughters/sons all the same age? Maybe I'm nitpicking, but man this felt sloppy and rushed.