I can't seem to find any info on this, I apologize if it's been addressed.
Anyway, as far as I can tell, I have everything in the game: 32 normal cubes, 33 anti-cubes (not sure how I got 33), all 9 treasure maps all 4 artifacts, and every area on the map is gold. I opened the 64 cube door, went through there and saw the pixel heart (at least that's what I assume that was), and then went through the ending door again. However, the ending was the exact same as the first time, and neither the "Hexahedronaut" and "Sum total" achievements have popped. I've clearly gotten all the cubes for "Hexahedronaut", and should have all the stuff for "Sum total" as well.
Is this a possible bug, or am I missing something? Could maybe that mysterious 33rd anti-cube be messing things up? Is this all a clever ploy by Phil Fish to drive me crazy!?