Clone Enemies (CE) is a mod for increasing the amount of enemies. It works on any Doom map, for any difficulty.
CE is a fork of the 10.5x mod. The difference is CE adds 4 sliders to the main Options menu, whereas 10.5x adds just one slider. This means 10.5x spawns the same number of clones for every enemy. I like spawning clones to spice things up, but the across-the-board cloning became too rigid (and downright ridiculous for maps with the toughest enemies). That's why I made CE.
The first 3 sliders of CE control the number of clones to spawn for the 3 weakest vanilla Doom enemies: Zombiemen, Shotgun guys, and Imp demons. You can clone each Zombieman up to 19 times, but the more formidible Shotgunners and Imps up to 9 times each.
The bottom slider is for All Other enemy types. All means All, so this includes Cyberdemons, Archviles, etc. It also includes any special enemies added by mods. Up to 4 clones are allowed here.
CE does the cloning immediately after a map is loaded. It also disperses the clones a bit, as explained here.
The main change for version 2 was adding a hidden CVar (meaning you can only change it in the console) called clones_chance. This is the percent chance that each clone will actually be spawned. The default value of clones_chance is 100, meaning 100% of them will spawn. The cool thing about reducing clones_chance is that it makes cloning less predictable. So, for example, you can use the All Other slider and a small chance, like 5 or 10, to potentially have a few difficult clones to deal with. It's nice to have another way to spice things up.
(If you use an enemy mod, see the next post.)