Actually Sis Puella stole the idea from an anon who was planning to start up their own Madoka game. They were basically trying to get their originally abandoned (according to the logged in comments they left here) "out there" before this anon had the chance to, so they even stole ideas they'd put in place and then let the game die.
Re: Madoka Game
It was a completely douchebag move of them.