the interweaving storyline is only one of the success element of the gangster epic, the other are music from ennio morricone, cinematography from, and the strong castings, and above all, director sergio leone. after the success of godfather, most gangster movies (e.g. goodfellas, scarface, godfather part III) followed its step, built the plot around violent, succession, legitimate, confession, etc. 'once upon a time in america' doesn't take such approach. throughout a long period of time, it is a story about changes, redemption, and friendship. as a symbol of unchange no matter of time, the watch is a great touching moment. i regard it superior than the 'godfather' trilogy.