Some guy made a game and claimed it was the hardest game on Steam. No one has gotten past the first level except the dev. The game claims to have 8 levels. People looked through the files and found out there was only one level and no way to beat it. #greenlight
What sold me on 4x was star trek birth of the federation. I'd actually played a very early space rts called star reach, but I'm not quite sure you could call it a 4x - certainly it wasnt considered a genre back then anyway.