One of the better incremental games I played in recent times.
There are some points that I feel are a bit lacking:
Buying prestige upgrades is tedious. Maybe add a checkbox that when active allows you to immediately buy the upgrade when you click on it or at least make it so you can repeatedly buy the same upgrade instead of having to click on the icon and then buy for each level.
I'd also like to have a way to see my active and passive earnings, this could easily be implemented through a stats page in the options or simply added next to the resources.
Anything else seems to have been mentioned in other comments already.