If you have not seen it, it's a four hour commitment but well worthy of your time. The film is soon to be released as was intended before the inevitable studio cuts took an hour off its initial 4 and a half hours. Director Sergio Leone was heartbroken by the edits and never made another film. Martin Scorsese is working with Leone's family and estate to resurrect the director's original 269 minutes; what he and many others regarded as his best work.
The musical themes are perfectly realized and bring certain scenes to mind immediately; particularly one heartbreaking moment where DeNiro's character, who has been reminiscing about his past imperfect, suddenly catches his older reflection in a window...
It was close between this soundtrack and Ennio's other masterpiece 'Cinema Paradiso' but there's more variety here and... it's just a better piece.
Watch, listen and weep.