I've always wondered this. After Mike kills all the heads of the 5 families and moves to Nevada what happened to the mafia in New york? Was Mike now consider Boss of Bosses? Did he select new leaders for the 5 families?

I think it wasn't a good move by the film creators to digress from the book in such a way. Nobody could hit every single crime family in New York and stay alive for much time after that, in my opinion (the same goes for the ending of pat 3). The movies are realistic for the most part, but those 2 endings don't make any sense to me. No one could successfully conduct a war against so many powerful enemies at the same time.

What do you mean? The end of the book and the film are pretty much the same.

You raise a good point, Roberto. In the novel, only Barzini and Tattaglia are killed. All that's said of succession in their families is that the Corleones kicked out all the "transgresssors" on their turf (presumably the Barzini people who'd invaded Tessio's territory as he complained to Vito and Michael in the fishtank scene in the movie), and whacked some Barzini "enforcers." The movie had Michael whacking Cuneo and Stracci as well. No doubt FFC did that for effect (four murders are more dramatic than two). Didn't make much sense, though.

Stretching for a rationale: I suppose that, by killing all the heads of the NY families, Michael simultaneously spread disorder in their ranks, fired a shot across the successors' bows, and in doing so reinforced the Corleone Family (under Clemenza) as the undisputed power. The reality is that Michael made that many more enemies.

N.B.: In a deleted scene from II, Neri shows Michael a photo of Fabrizzio and tells him that Fab came to the US in 1956, "sponsored by the Barzini fFamily." So, there was someone in the post-massacre Barzini family who wanted to pay a debt to the murderer of Apollonia.

Good post TB. So much of the difference between the film and novel is dramatic license. One difference is the use of automatic weapons in the film and pistols in the novel.

Right, Oli, much of the Great Massacre scene was, technically, ridiculous. Why dispatch two guys armed with Madsen submachine guns to whack Tatt and the hooker he was in bed with? Why did Fat Clemenza climb all those stairs to blast Stracci in an elevator with a shotgun? And why arm Neri with a six-shot S&W .38 to kill three guys--including Barzini, who was running away?

Even more ridiculous: He's kicking one of the bodyguards back into the elevator. Did Clemenza know that Stracci could only afford physically handicapped bodyguards?

Clemenza probably kicked Stracci so he would not run into Clemenza by pushing him over and the gun with him, The Bodyguards would then have time to pop Clemenza.

It could be done, Michael made a deal with the Underbosses or the next person to be in the throne that he would make them boss by killing the heads. Michael then would of had a peace deal with the new boss. No other family would go against the Corleone's because they would be so feared that one family took out 4. More criminal's would of joined the Corleones after hearing this and the fame the Corleone family were having at the time being NO.1

What's wrong with that? Tattaglia could of been armed and probably had more more than any other family by his Prostitution Rings and Drug Rings. Clemenza knew Stracci was having a meeting on that floor and would of popped Stracci either in the elevator or the stairs, Stracci was a handgun man, Clemenza would of destroyed Stracci and his wiseguys with a shotgun. Neri was known to have a good aim and probably would of been known to other police cops because he was an ex New York cop.