They have only started and the list of games that can be added is small now, but it will increase with time.
Maybe they'll add the EEs later.
"Today, we're launching a new program called GOG Connect. The premise is simple: connect your Steam account and add your eligible games to your GOG.com library (at connect.gog.com).
Whether you're checking us out for the first time or looking to copy over your previous purchases, GOG Connect gives you DRM-free versions of your games, along with digital extras and the freedom to choose between standalone installers or the optional GOG Galaxy Client. It's our take on game ownership and we say: why buy the games more than once?
Thanks to our awesome partners including Deep Silver, Harebrained Schemes, Jonathan Blow's Number None, TaleWorlds and more, over 20 games can be added to your GOG.com library if you previously purchased them on Steam.
You can view the full list of games on connect.gog.com
- The Witness
- FTL: Faster Than Light
- The Incredible Adventures of Van Helsing: Final Cut
- Galactic Civilizations 3
- Trine Enchanted Edition
- Saints Row 2
- Shadowrun Returns
- The Witcher: Enhanced Edition
While GOG Connect will stick around, the games available will come and go. These are limited-time offers made possible by participating developers and publishers, so stay tuned for more games to come."