It would be nice if the "progress goals" tab either saved your scroll position, or was just sorted newest to oldest.
As I progress down the goals, there are more colors to get, so I'm checking more often. But I have to scroll down to the one I'm working on.
Just a small nitpick :)
I really like the concept, and the execution is really neat. Lots of idle games quickly become "okay, now wait 3 hrs and come back when you can afford the next upgrade"
I'm enjoying the quick pace, and the strategy of trying to pick a gradient that includes multiple colors from the goal.