I've just finished the base game and I have to leave a comment to say that this might be the best walkthrough I've ever used on this site! Brilliantly written, very easy to follow and concise, I can't praise your work enough!
The only thing I ran into trouble with, and it's extremely minor, is in the Southern Observatory section of Brittle Hollow, where you say "After getting caught by one of these beams and landing on solid ground on the other side, glance to the Southwest (note your player arrow on the map). You will see several more rocky platforms across the gap.", there was a gravity crystal wall I had to climb to a higher ledge to see these platforms. I landed in the gravity beam on the left and thought I went the wrong way so reset the loop to try again. I don't know if you have to do this with the one on the right.
Again though, thanks for writing such a great walkthrough and I look forward to the DLC page