The original BluRay was gorgeous, but scene release groups are fickle. There was a previous attempt at this encode. It was fine. But "fine" isn't good enough for the sequence where Laurence dances to "Come as You Are" or the slow-motion explosion of a room full of books.
This usually means the first version released had a minor technical glitch (like a subtitle sync error or a frame drop) and this "repacked" version is the corrected, definitive copy. The Film: A Visual Riot laurenceanyways20121080pblurayx264iguana repack