Thanks for all the details! I used the wrong word (also in the change log, I'm afraid). It's not just when minimized, its when not visible, as you say. Credits now continue to accumulate, just a normal income does. Since your window was hidden, progress would now be much, much, even though Arena is still not running. For better or worse. I can probably just scale your results by a factor I need to figure out. The order of things should be about the same.
Edit: you spent 11.5 hours going from 1 to 11 diamonds? The new rate doesn't look to be faster than that . Hmm... I think it will be left as is, it's a slow process to do thorough testing. Thanks again!
"/poke: can you really ask your customers to keep your prog visible at any time to progress?"
Unfortunately I can't fix that now. If it was built from the ground up for this I could at least alleviate it, but not now. I've seen other idle games with the same problem, ex clicker heroes, which tries to simulate your time away when you get back.
Running as a Windows build there wouldn't be that problem and I'm going to include one when I think this is a version 1, which I kinda do now. Did you notice anything that is must-have, besides the Arena problem?
Thanks for the testing, helps a lot!