Yesterday, some goober cut a cable in my area killing all internet connection. Since I couldn't work, I thought I'd play a single player PC game - Witcher 2, perfect! No, not so fast. It wouldn't launch, something about a connection. Why does my single player game need internet to play!? Is this a GOG thing? Are all my GOG games going to need internet to play?
None of the games on GOG require an internet connection to play, but the Witcher 2 does require one in order to install patches (usually). There was some weirdness with that one needing a one-time internet connection the first time you launch the game, but then I think that requirement was removed later... does anyone remember exactly what happened with that? The retail version had DRM online activation which was later patched out, but I thought that GOG's version NEVER had any DRM, but I could be mistaken.
Was this your first time trying to run the game?
Anyway, the Witcher 2 is kind of a special case, other GOG games definitely do not require an internet connection, and the Witcher 2 is probably only saying that it does due to some issue with getting it patched. If you have another place where you can access the internet and can manually download the patches and put them on a USB stick or something, you should be able to patch your game and then play without an internet connection. Or just play any other game from GOG instead, those should work without any trouble.