Recently, I had a problem with installing a GOG title, and the only recommendation so far was "Oh, you got probably a corrupted download, download again and try once more". Needless to say, that was not the case.

I could have save myself another 300MB download if a checksum hash was published, allowing me to easily check the integrity of the downloaded file. Better yet, the installer itself could calculate the hash and check it against the known proper value.

Linux distributions and various other software sources use this, why not GOG?

I think the GOGWiki has MD5 hashes for various installers.

Someone more familiar with the wiki can likely tell you more.

Assuming you are talking about windows installers, the digital signature takes the part of the hash check for single files, while multi file installers have an integrity option check in the options screen. Using the gogdownloader to download the files also helps with hash checks for both windows and mac installers.

If you are using linux, try the lgogdownloader which does have the option for hash checking. And you can always ask Sude for information on how to grab the xml file with the hashes from GOG, the same one that the downloaders use to verify the integrity of the files. Not sure if anyone is updating those anymore though.

Wishlist.