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Downloading with the Gamersgate downloader works, as does installation. The game will run if settings.txt in the EU3 directory is changed so that master_volume is set to -1. The game will run, but there will be no sound. Singleplayer will work and the launcher will too.
What does not
Sound does not work at all, and the map's borders are scrambled up a bit. The movies that play at the start do not play.
What was not tested
I have yet to test multiplayer games or switching mods with the launcher.
To get this to work. you must install dotnet20 with winetricks. Also, it relies on some native DLLs that are mentioned in the various EU3 Wine guides.