This is super weird, looks great and seems easy to use as a standalone or to slot into an existing campaign. I particularly appreciate that you have taken the time to call out "why cube" and "if cube then what," as these things are often skipped over in short settings and adventures. My only real note is that the fonts are both kind of hard to read sometimes--one of them looks very blocky in bold and the other has some wonky descenders. But all in all it's great, good job!