Not really my type of game, so I can't say much. Played till score 42 and didn't see anything except green cubes. I saw that there are pink cubes in expert mode. So... does beginner mode only has green cubes... forever? If no, adding some kind of 'promise of content' would be great, because just increasing score is not enough to keep my motivation.
Probably making the ball drop a shadow onto the cubes would help with height/depth perception, now it's really hard to understand where the ball is relative to the cubes. Maybe also adding 2 next cubes instead of 1 for beginner mode would also help the beginner.
I guess aesthetics can be improved easliy by adding some kind of skybox.
The music was too much for me, but luckily we can easily disable sound in browser tabs, so I guess it's not really an issue.