Copied duke3d.gpe, plus duke3d.cfg, duke3d.grp, defs.con, game.con, and user.con from the Atomic Edition to /Games/Duke3D. Edited the config file for the sound settings (FXDevice=0,MixRate=1600).
All I get is a black screen. I've tried setting ScreenWidth/ScreenHeight in the cfg to 320/240...