I have the same problem, I thought it was because the files were named ending in .001 .002 etc instead of .7z but even when I renamed them they won't open and I can't extract them. Not sure what the deal is, anyone able to download it in parts and extract? If so what did you do?
Aaahhh - these parts are from a 7-Zip splitted compression.
This would be the file list from MEGA for BR R15
You have to store all parts into 1 folder - then rightclick the file .001 and order to extract via 7-Zip to (a folder where you want have the game), 7-Zip is doing the rest. So far all parts are correct downloaded.
But as I recommended multiple times: if this don´t work, download the whole file via torrent.
I can give you help, if you don´t know how.
7-Zip is strongly recommended, WINRar is known having issues with these files!
EDIT 03-2024: updated to R15