GOG are celebrating 14 years of existing with a big sale on lots of games, plus you can get a free copy of Master of Magic Classic.
For the giveaway, simply be logged in to GOG and scroll down to find the giveaway banner. They only have a build up for Windows but since it uses DOSBox you can easily run it nicely on Linux too. You can claim that game free until Sunday October 2nd, 10 PM UTC.
The Elder Scrolls V: Skyrim has also now landed on GOG with the Anniversary Edition and Special Edition. GOG said in their email that their version has been tweaked so you can get the Anniversary Edition content without the need for Creation Club access and naturally it's fully playable offline.
As for modding it GOG said:
As the game is recognized as one of the most modded titles in the history of video games, support for community-created content in Skyrim was one of our top priorities. The GOG version is compatible out of the box with most modifications mods via Nexus Mods Vortex v1.6.12 and newer. Support for mods requiring Skyrim Script Extender will be added later today. Additionally, GOG is preparing something special to provide an even smoother modding experience – expect more details soon.
The game has long worked in Wine / Proton so it's another option for you and good news for GOG fans.
As for the sale there's 900+ discounted so do let us know if you find a good deal.