This is a direct sequel to Yuuka Ryouran, as well as other Zounose stories in the same compilation this was released in (Suwako vs. Space Suwako, Go! Go! Around, Crow and Rabbit and Mazi-Magi).

While Mugamubiru extras have always had some elements taken from its compiled stories, this one in particular makes it a lot more obvious where it stands in the timeline (i.e. at the end of it) since some of it can't happen if the previous stories don't happen first.

I'm always impressed by how Zounose has created his own vision of Gensokyo, and this cemented it even further.