When Leone finished making the movie it was 229 minutes (3 hours and 49 minutes) and started with an old character (Robert De Niro) remembering his past; it then showed him as a child and as a young adult. We call this flashbacks; it can happen in movie but certainly not in real life. But when it was first shown to American audiences it was made much shorter and set in chronological order; meaning the movie first showed the characters as children, then as young adults and then as older adults; or 'from start to finish'. We call this "chronological"; this is what would happen in real life. Many people agree that the longer version is much better than the shortened chronological version.