1. Download & Install GzDoom http://gzdoom.drdteam.org/page.php?pa... 2. Put Doom 1 & Doom 2 .wad into the Main GzDoom-Folder 3. Just drag & drop the file ALIENS The Ultimate Doom Beta .pk3 onto GzDoom.exe! 4. Be scared and have fun!
(Remember to bind your flashlight-key!)
PS: Yes, I know, the Marines are friendly. Don't shoot them! ^^ (I panicked.)