A quick test shows that this is most likely another set of tiny bug fixes that were likely exploited at some points. Such as Tiny Marisa's dead pixel was finally fixed. And now the music will stop playing when you pause the game. I know there were more odd bugs, so chances are those might of been fixed too. So unless someone is going to spend some time digging, I don't see any extra stages in this patch.
A translation of the read me would be most appriciated.