this is really cute and fits the puzzle category very well ! I could not understand what the darker squares meant, those did seems to change anything ? I) might have missed a bubble though as i could not get back to the first cube bubble even on restart.
At first i thought because of the theme that i have to slide until i collide with a dark side (a mechanic very often seen with the ice theme), so i feel like the theme while looking really good, is not a good match with your gameplay.
Overall really good quality game ! very well polished and works well :) I personally just did not go past level 4 as i did not enjoy the mechanic so much.