I have to upgrade one level at a time, right? I can`t just upgrade to the top level?
So, upgrade to level 2 costs 20,000
upgrade to level 3 costs 60,000
upgrade to level 4 costs 80,000
upgrade to level 5 costs 150,000
upgrade to level 6 costs 300,000
upgrade to level 7 costs 400,000
upgrade to level 8 costs 600,000
upgrade to level 9 costs 700,000
upgrade to level 10 costs 800,000
The total costs for upgrades is 3,110,000 and at the end of the game I earn 1,000,000 - am I missing something?
Yup you definitely are... how much are you earning on robots from 1-20? Also with upgrades, you defeat them faster and get your rewards sooner that way. Level 20 1,000,000 is just a bonus to use for upgrades in the next round.
Also you have to factor in the promos for bonus attacks, as well as from share bonuses. Your upgrades are worth a lot more then.