Something else I can't help but wonder.
Did there used to be more creds earned? Maybe an increase in rewards as the Overworld levels progress?
I ask this as I am saving up for those Production rooms and Generators which are kinda pricey, especially when 25-35 is as much as I can expect for a reward be it on level 1 or level 101. I did just get an Orbin Generator as a Puzzle reward though, so that saved me 5.5k creds.
I ask, because this must have taken a while
Then again, you are the dev so I imagine that cash and objects aren't as much of a hassle for you to get than they are for me.