I thought that the idea of having the two colors that you're swapping between was a fun idea. It makes it so the player has to decide what color they want to risk empowering before starting a round. Like I personally spammed one color early on so that harder content early on would have less power on the color I didn't choose, but I could also see why a player might want to simply switch off between rounds for a gradual rise in difficulty. This kind of design where you have to make decisions based off of risk and resources is what really drives player engagement. Keep up your smart design sensibilities!