I found the main mechanic a bit unclear. The color of the boxes led me to believe I had to group them together by color and it wasn't until only a little time was left that I realized that was not the case. I think also the game could benefit from snapping for the boxes, as well as a more forgiving selection. I think the core concept is good though, I liked the idea that you'd build bigger and bigger boxes.
Some bugs:
- Selecting Exit does nothing in the HTML build, just freezes the game
- Music stopped playing after a single song