Nice, this is a great game! All the puzzles had just the right level of difficulty. I felt challenged at every level but was able to figure all of them out with some critical thought. I like that the puzzles help to teach you how the color-spreading mechanic works.
I think it would be nice if there was a way to see which levels you've completed already. I found it confusing to go to the level select screen and not know where I left off.
I also found it a little hard to tell exactly how much color was in each block. The graphs were nice, but I wonder if numbers would be even better. Maybe a number above each bar of the bar chart indicating how much of that color is in the block would make it easiest?
I didn't realize until the last level that white blocks are allowed to have an excess of some colors, as long as they have enough of each color. I wonder if that's intentional or a bug?
Anyway, this puzzle mechanic is pleasingly simple, but it leads to perfectly complex puzzles. Great puzzle game!