ZDoom, or GZDoom for full freelooking. Skulltag for online deathmatching or Cooperative play. www.zdoom.org grafzahl.drdteam.org www.skulltag.com These are new Doom game engines. To use them, copy the files you download into a folder on your desktop. Then copy a Doom IWAD file into that folder. It is the largest file that Doom installes. Or you can find it on your Doom installation CD. The Iwad is called Doom.wad, or Doom2.wad. Then double-click on the ZDoom exe file in the folder.