Posted June 07, 2018
HunchBluntley: One reason they split them up is so that, if one file gets corrupted during downloading, you won't have to download the entire game again (some games these days have downloads of more than 30 gigs), only the affected "chunk".
Some old filesystem only support filesize up to 4294967294 (2^32-2) bytes. GOG used to make mistakes and provided 2-bytes-larger (2^32) files.
But recently, GOG only provide Windows installers that have maximum filesize 4294967294 bytes.
Linux almost never have this limitation, so GOG's Linux installer often have filesize up to 10 GiB in a single file.