The game plays well as a tribute to the movie. Other than that, the game feels very outdated.
The city of NY is very bland, and most streets look the same. You have to stick to the roads, and there is very little sense of freedom. For instance, in "Mafia" of "GTA" you can use shortcuts over hills, grass, jump off a bridge, but "The Godfather" is a lot like "Driver": you cannot go but where the game allows you to go. There are too few car models, which don't handle or look particularly realistic. You can't even see through the windows. The character of Michael Corleone doesn't look nearly as realistic as Vito, Sonny or Tom Hagen. It is also one of the few characters which are not voiced by the original actor (Pacino didn't want to do it because his voice has altered due to heavy smoking). But why his appearance is so far off, is beyond me. Also, the story doesn't make a whole lot of sense to people who haven't seen the movie. I don't think those are the target audience of the game, but nevertheless, the game should provide a coherent story on it's own. And lastly: while the game follows the movie's plotline pretty closely, it makes no sense that the player becomes the don himself in the end.
On the plus side, and in contrary to "Mafia", the city feels more "alive" because there is more to do (extorting shops) if you're not on a mission. Also, the combat is pretty fun. Other than that, this game looks and feels outdated, and reminds me of Driver, which was made almost 10 years ago.