Also couldn't figure out what to hold to get the ending, i think i've definitely made it through more than 5 tiers, since the little dots fill out in the back button on the lowest nest.
I also can't figure out what clicking the fifth resource in the upper left box does? It just uses up purple and yellow resources
And i think there's supposed to be automation tied to the lower right, but i can't get the curved arrow resource to do anything