First of all if i missed an answer to this sorry : ) On my old PC with the GTX460 the Hi Res pack works great (impressed).all I did was opened the 7zip to a named folder on Desktop then copy GRP file over from Duke3D worked great.
Now on other not so old PC with a GTX570 done exact same thing, but this time it looks a wee bit better than original version not as good as other PC and the enemies are still 2D sprites tried this several time now : ( any idea? greatful for any help.

Sorry folks just tranferred files from older pc (DUH!) working now still dont understand though but it works lol