I remember getting deep into that game, trying to make my own levels with megs of RAM and having things crash. Changing all the sprites on some of the mobs, recording my own sounds and replacing various noises in the game. I learned how to strafe using 100& keyboard (couldn't look up or down in that game), and dominating the evil. Good time to be a teenager. I still think some of the secret rooms in that game were some of the best.