The purple door opens when you start a new run
On the second day.
Yup. Then it stays open for three days. I think I have it set to open when you load a time machine file too. Then there's also a third way in there if you complete a series of events with the ghost book
By starting a new run you mean using the restart button?
also, regarding to the original question, what counts as completing the course and how do I get the stronger version?
Yeah, I mean with the restart button. And for now, it counts as completing things if you beat the Mysterious Rogue
