Aliasalpha: It was suggested I add this to the features list, it's more of a program suggestion.
Given the number of good old games that had multiplayer that only worked on a LAN (be it from non-routable or unsupported protocols or just because they were desgned that way) or via modem, what would be nice is a GOG specific LAN emulator so people who buy gog games with multiplayer can play them with fellow goggers.
I'm thinking the way this would work would be a small peer to peer network / launcher application that you run before starting the game and establish a connection to a fellow host which will be used through the entire gaming process. Some form of voice chat support would also be bloody nice but it'd be icing rather than cake.
If the application also functioned as a launcher, starting the game from this app could help it identify the program to intercept network traffic from. Those network requests would be captured and re-framed so they are in a routable format with a destination address for a known network.
I reckon it'd be worth the usual $6-10 price
it might not be practical to do everything, especially modem play, but that Hamachi program makes it seem potentially practical and wrapping one protocol inside another shouldn't be that hard. As I said voice chat would be icing but xbox live can do it and you don't want people saying xbox live is better than GOG do you?