Back Door is a form of malicious feature in which the program is configured to respond to commands sent to it from the developer. A Universal Back Door is an ability of the developer to remotely change the program to do anything the developer desires it to do. Sometimes Universal Back Doors are called "Auto-Update".
This comment thread is for people to document various implementations of this malicious feature.
The multiplayer, or the lack there of, at the moment is so utterly broken and so lacking of being properly made that for a long time, I was just not bothering with it. Seeing it as something unnecessary. Something that does not need to be touched, because other things, like the story or some gimmicky thing is more important for the game than the multiplayer. But people's demands for it didn't stop. So I thought now is a good time to actually properly design it.