Thanks for playing and for the nice review, pointing out almost every little aspect - this inspiring and means alot! Its not a surprise that you nailed such an environment with such a nickname :)
Upgrade thing - yeah, its not obviouі at all: Every upgrade have a "scrap cost" that represented by the number at the bottom of upgrade screen. And amount of the scrap you currently have represented by the number of lit "square dots" in "storage" section (right of the claw) - too much counting indeed