Lousy instructions, no music
1. No instructions about the type of blocks, or how to destroy each of them, or about anything. And that sentence at the beginning of the game is NOT an instruction.
2. There is no music. A game like this needs some ambient music. The predictable path of the balls gets boring, so you need a good track to keep my attention.
p.s. this can be enjoyable game, if you put more work on the design. Make it appealing, many people will like it even if it is crappy. And this game is not. But it has crappy design.