Creepy, very much like Obsidian level 6.  Like a slow tribal march of doom.  Also seems to capture the feel of the Saturn songs from D1, especially with the transposed part at the end.  I'd suggest a reverse cymbal just before the part that starts at 0:50, or some sort of crescendo while the choir note is being held down, to increase the effect of the tension that's apparent there, imo it would work a lot better.  I keep expecting the second sweep pad note (at the beginning) to go up by a third instead of down.  My other impression is that ER in Muchikuchi is meant to be a callback to this song.

I get the feeling that you fight a boss on this level, and I'm pretty sure that boss, if it exists, is Doniel.  From what I read on the old version of your site, he's very much the Darth Vader figure (blindly loyal evil follower).  I doubt he's Pumi's father though .

I can't believe I forgot to rate something this awesome.

@alieo:

One song for each level including secret levels, so that counts for 20 in total.