Very well done, the style is very consistent around game and menu, very nice.
I have, if i may, two suggestions:
- It would be a good idea to introduce the 'destroy block' function more visibly: I was about to comment 'too hard' when i finally discovered that you could actually do that. I can imagine most people just reading the left side to get controls and then they just start playing. Since it is a pretty unexpected feature, you could make it pop or blink at the beginning, or maybe show it near the stone forecast.
- Maybe you could add some sort of penalty for using the destroy function. Right now, it is too easy, i could have played for hours if i wanted to, but after 20 lines or so, its kinda idle. After you destroyed a block, the next block could come quicker for example.