Good idea, regarding the colors. I was hoping the particle effects could show the color was being expelled from the character, but that's definitely not super clear. Level design is definitely something I'll consider.
I think the size of those objects is important. They're basically bullets that will kill the character. If they're too large they become very difficult to dodge. It's an important element to a lot of the levels, so I don't want to tinker with it too much. That said I could try adding a mode of the game that doesn't use colors at all (all white). It may not be the optimum experience for color-blind players, but it would be a cheap way to at least make the game playable for them.