The mechanics & synergies between the different cubes were interesting and definitely fit the theme. I especially liked bouncing on the yellow one, it was really fun.
In regards to the graphics, be careful with the differences in sprite resolutions and aesthetics. The door for instance does denote quite a lot compared to the rest of the environment.
Edit: The distance of the camera gave me quite a hard time doing some jumps, sometimes requiring to aim for a platform out of screen. Could be nice to zoom out just a little or at least in the levels with wide jumps or significant drops.
Great work nonetheless, kudos to you!