Some usability suggestions:
1) Leave room on the left to display navigation buttons whenever you block the game screen with a menu. Having to view your angel upgrades, close the window and then re-open your angel investors menu to check how many angels you have if is a 3-click process. It can easily be two.
2) Likewise, display your money/AI in pop-up screens where it's relevant. Having to close the window just to check how much you have and re-open to confirm purchase is disorienting .