Originally Willis turned down the first two Godfather films before Coppola told him they wouldn't look the same without him.
Willis said that it was the colour that stitched the Godfather films together.
The novel also led to the series of "Godfather" films by the director Francis Ford Coppola.
Francis Ford Coppola, director of the "Godfather" films, consulted briefly with the game team but did not like what he saw.
He made cameo appearances in all three Godfather films as a conductor.
Paramount is making new digital masters of the "Godfather" films for reissue, as single-film discs, late next year.
They discuss his father's involvement in organized crime and if their family's life is similar to the one depicted in The Godfather films.
Perhaps the most familiar case is the second "Godfather" film (1974), which explores Michael Corleone's youth.
For them, there is wisdom to be gleaned from the first "Godfather" film: Leave the gun.
It's the epic story of America refracted through one family in the "Godfather" films.