Here is an awesome map that I made. You are on a random base on Mars and there are zombies everywhere so you have to kill them. (duh) Using cheats for this map is lame. Don't you want a challenge?
I can beat it without cheats so you probably can. It's hard though so you won't beat it on the first try. ;) Of course, you can kill the cyberdemon no matter what you do so if the only monster left is the cyberdemon then you win!