I was playing this co-op with my girlfriend, and we had a very fun time with it! My only real feedback is that it was somewhat hard to figure out which color we were being asked for on some of the puzzles, and the fact that the very satisfying "space filled in" sound played whether or not you got the color right really tripped us up on the first color mixing puzzle. We replayed it several times in a row with almost the right color, and couldn't figure out why the game wasn't progressing, until we noticed the red percentages on the bottom of the screen.
Overall though, very cute, cozy, and a very enjoyable co-op experience! :) Well done!