Place The Key maps work through a redstone/command block machine encased in bedrock, which looks for a win condition. They are based in carefully selected survival worlds and typically very small to download, though the map can include distant noncontiguous chunks. You are playing survival Minecraft, with a twist, and typically in speed-run fashion—trying to complete the win condition.
In Nightmare Moon, pull the lever to begin the game, and the game machine will begin a night that could last forever… unless you slay the Ender Dragon, get its egg, and place the egg atop the machine's blinking light! That is the win condition.
Sound easy? There's a catch. The player placing the egg (the 'Fluttershy') must never have killed anything, even food animals. All players who have killed will be physically flung away from the machine when they approach it!
There are unusual spawners you can exploit, and heavier diamond ore near spawn. It's for speed-run cooperative play, with grindy aspects cut back for the benefit of YouTube LPers. You'll love the cow popper!
(Further tips: Hide in the cave right at spawn to start, there are instructions in there. The cow popper has to have cow spawning conditions to work. You have to dig the dirt down a block and then let grass spread to it, but beware disturbing the gravel bridge! You can make a bed and sleep, but it will only reset your spawn, not cause the night to end. That can be useful in the end-game, though! There's netherwart and soul sand at one of the blaze spawners, if you can get it. If you do go into the Nether, you will probably end up right on top of a fortress. The Fluttershy has to have kills=0 but passive damage doesn't count, so that player can use water and lava buckets and even flint and steel, if they're good. Our Fluttershy is a Minecraft monster and nearly laid waste to more mobs than the normal players! And she felt just awful about it, too! Finally, do not allow mobs to blow up the machine, or you will be trapped in eternal night. Our Fluttershy played with creepers near the machine and blew up the internal workings requiring a between-episodes fix in MCEdit, and you'll need that machine operational to win! If the light still blinks, you should be good.)
Before you ask, the pony theme is for two reasons. Our playerbase is mostly bronies, an MLP character gives the map its name and mission (Nightmare Moon literally did try to make a night that lasts forever, and in this map she does exactly that) and Fluttershy is a pony character who wouldn't hurt even a fly. In this map, at least one player must end the game with zero kills to approach the machine and place the Dragon Egg, and who better than Fluttershy to play that vital role?
Ninjashy mode: the Fluttershy can kill mobs all she wants as long as it's by lava etc. (Our playthrough was Ninjashy)
Veganshy mode: the Fluttershy does not attack anything, or even wear leather armor.
God mode: play singleplayer—or with no Fluttershy—and find a way to place the egg on a working machine while it flings you away. It is rapidly teleporting you up and back several blocks until you're out of range, and doesn't care if it drops you to your death. This SHOULD be impossible to do: feel free to attempt it by placing any block on top of the running machine, if you've killed. If anyone does this, I'd love to see video evidence!
Enjoy Nightmare Moon, and let me know if it's working for LPers, as it's meant to!
If you're trying it solo, let me know if you were able to place the egg at all!
I'm considering making it so that the Fluttershy can have killed ONE mob—the dragon! If so, you can still play it classic with no kills, but playing it solo might be possible through ingenious methods. You'd have to be careful to not kill anything else other than by passive means.