The white and black materials are called Meteorite and Dark Matter respectively. The English DLsite actually translated the text, so you can see what the area names are called and what the items are called as well. So yay, no more grinding for materials! They're actually relatively easy to get if you time your jumps right, but there is one where I had to abuse a ledge glitch or whatever where you can stand on the very end of a spike platform safely. There are quite a few golden chests thrown about the extra area, and they contain the white and black material used for item boosting or crafting.
I went through on very easy first to see what I was in for and what was in there, and the first part is a few platforming segments with lots of everyone's favorite hazards, instakill spikes.
Okay, holy shit, this extra area is fucking hard.
