Bundle files could be different: encrypted (worst scenario), protected (with hash check), not encrypted/protected. In this case protected bundle contains only videos which are biggest part of the game size, but usually images does most size of the game which can only be repacked (unless its put in external file like for this game, happens very rare) to reduce game size significally.
Anyway
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(install fix on UAGC v2.7.6 or v2.7.5) to deal with video_assets_all_f86973e15ddf8909300491af61f5c656.bundle: 3.42Gb -> 1.18Gb (ziped, after compression in UAGC). New fix also should deal with possible problems of compressing voiced VP8 videos in all engines where it using (QSP Awesomium and Custom engine), maybe it's worth to compress 1st part again just in case...