phanboy_iv writes "Fans of both of the Raven classics, Heretic and Hexen, have been trying for almost a decade to convince Raven Software to release engine source code for the games under the GPL, much like the DOOM engine on which both of them are based. Well, they finally did it! Source code is available at Sourceforge. Both of these games have had the source available for a while, but under a restrictive license that hindered ports and modifications. Now, thanks to dedicated fans, that's no longer a problem."