It's just "Urapani!". I'll quote what I was told about what the "Ura" means:
Ura means "back side" more specifically. And it is common to denote stuff that is "more" than something with it. Take the game of Taiko for example - it has the hardest difficulty that is called Taiko Oni, and then there's even harder one that is called Taiko Ura Oni. Meaning that there's something "behind" the highest point.
Essentially, it's just an in-house romhack of Amapani. As a fun fact, if you've been keeping Amapani up-to-date, you'll find that they've added the new character abilities to that as well, so the two games are now completely identical in terms of controls... It's just the levels in Urapani are more likely to make you throw your controller out the window. :V
Anyways, I'll just put this here:
https://www.youtube.com/playlist?list=PLoUS23R3h5anM4pbScyYBijvFoXgHrMnJCurrently, the only thing we have left to do is the extra world(s), which will be all kinds enjoyment for everyone involved.
I'm still figuring out how to get some of the grimoires, esp. the one in the end of World 4. Any tips?
If you mean the one on the boss stage, then
Either that, or if you have multiple players, you can just cheese it by abusing respawns. :V