Half a game deserves half the score.
The Godfather game itself is a half baked GTA clone. It looks pretty with some detailed models, and has some interesting features such as the fighting but the game world is the most tedious, unimaginative waste of space going. Don't be fooled by claims that it is the whole of NYC. This is a horribly simplified NYC where everything and I mean everything is fenced off. Your character can't jump, climb walls / fences, or do anything except walk or drive along the roads set out for you. There isn't even a subway system in this New York!!! To break the monotony of the world, there are various rackets and stores to extort, but they're all employ the same boiler plate graphics, i.e. all the florists look the same, all the hotels look the same etc. The vehicle selection is also horrendously poor, featuring a handful of generic vehicle types. It means driving around is as boring as the world itself.
The biggest sin of this game are the missions. Once you've played half way through, there is little reason to go any further. At that point all the Corleone missions end and all there is left to do is bomb five compounds and take over every store, racket and warehouse in the city. Sounds exciting? It isn't.
Aside from a couple of textures, every compound is also the same boiler plate model right down to where the mobsters come out from. So after you've beaten the compound once you still have to repeat 4 more times. Then repeat for every boiler plate shop type, racket and warehouse. By this point you will be utterly sick of the game. You'll even figure how to kill most of the mobsters from a distance without their dumb AI even realising you're shooting at them.
A final note on the voice acting. Generally it's very good but the Marlon Brando impersonator is not convincing. As far as I could tell, the real Brando voice is only used in a few clips ripped from the movie. The rest of the time you get a mealy mouthed impersonator. And Al Pacino's voice and likeness are completely absent. The plot itself is an absurd backstory to the movie where your character is more like Rambo than anyone who would inhabit the movie universe. The body count runs into hundreds by the end of the game and for that you must endure a cornball story involving love and betrayal.
Again, this game looks attractive initially, but it is half a game. To think this game was delayed 6 months... Perhaps they should have delayed it another 6 to actually finish it.