100x multiplies the amount of doom enemies by, you guessed it, 100. Enemies explode into multiples of hundred as soon as the map starts. Due to collision problems, you are able to walk through monsters. Most monsters projectiles pass through each other, making it harder. Ammo on the map is also timesed by hundred. Don't try this on NUTS maps! If you have a weak PC it will most likely crash on you. This amazing challenge is so far ahead of it's time, that you will have to wait for something like windows 10 for example, and that may not come out until the next decade. The WAD was based on 10x by Cutmanmike.
Cutmanmike for the idea.
Occasionally monsters will pretend to be dead, but will get back up when you shoot them. I have no idea what's casuing this but it's funny so I won't go nuts about fixing it.