But I just made it to the core the first time, and wanted to point out that when running to the very north end of the platform, the party button text box pops up. I'm not sure if that is intentional or a leftover, but getting the party all there does nothing. Also, in Vaigel's speech, when talking about the air there was a bit of a typo, with a sentence starting "The you" in one of the paragraphs.
Otherwise, I am happy to have reached that far, and look forward to seeing what Three Rings does in the future with this game. For now, I will attempt Tier 3 until I can get there without needing a rez or two... (using only non-maxed 4* gear is probably not helping me any)