I'm truly mystified as to why they couldn't just tar up everything except the assets and have users just untar the file over the previous install. That wouldn't bring the download to the 111MB that Windows users get, but that ought to cut at lest 4 or 5 gigs off the download.
Yes, that doesn't look professional. I hope GOG will sort these kind of issues going forward.
Somebody referred me to a post by Judas and apparently inXile changed every single file in the archive, hence the redownload.
I'm fortunate enough to not have caps on my internet, but it's a 6 hour download and God help me if some of it gets corrupted along the way or something interrupts the process as resume feature for download managers is somewhat unreliable.
I'm still trying to figure out why downloading via the Windows or OSX Download manager isn't a possibility. Granted Linux users may not have access to Windows or OSX, but most will or at least know somebody who does.
I'm also puzzled as to why they didn't split the files as Linux Mint, and presumably Ubuntu, have split built into the OS.
EDIT: Also, this is a good reason why they should offer release notes on the same page as the update link. That's what pretty much everybody else does and it helps people remember that the information is out there.