Quake Epsilon is a graphically enhanced build of shareware Quake 1 for Windows/Linux/Mac, which can be upgraded to the full version of Quake along with it's mission packs Scourge of Armagon and Dissolution of Eternity by copying the full-version .pak files into the correct folders. It's made out of the Darkplaces engine and many mods from members of the Quake One forums and elsewhere (full credits on website) as well as my own work. These builds do not contain any pirated content. Just simple unzip-and-play stuff.
Soundtrack is Sonic Mayhem's alternative "Methods of Destruction" Quake soundtrack.