Ah, didn't see that all things increased in cost, and didn't notice the (2^x), it just looked like 2 :D Now it makes sense, and yea individual cost would makes sense, but for this game jam it doesn't really matter, your game idea is understandable.
I guess you misunderstood my idea ... I understand, it's not an easy idea to understand ...
Increasing the cost of all upgrades is intencionally done, and this is done so as not to make the player buy only the least expensive upgrade mindlessly, but to make him think on which it's the most useful to achieve the overflow.
What I really meant was that you spent the individual digits of the binary number as coins you can spend... so as to make the game even more tactical... I'll provide an example of that idea, in order to make it more clear...
EXAMPLE:
if this is the binary number 00000000000000000010001001011101, and the Bold are the green ones, you can buy as many upgrades as the 1 not bold, 3 in this case...
As for now, this situation is not really possible, because the game dosen't work like that...
(I hope I managed to make it as clear as possible...)