Awesome
Wow, that was pretty intense. I didn't have high hopes for this game at first, but now I'm just waiting for my arm to stop aching so I can play again.
What I would say has most likely already been said multiple times already, so I'll just really simplify it:
For some of the color schemes, it was just way too difficult to differentiate between the blocks. During the black and white parts, I started getting a bunch of irons blocks because I kept thinking that the stones were just gray blocks. The fact that I have really crappy color vision doesn't help much either.
There's nothing else really I can mention. Except maybe that having the gravity shift to the sides would have been an interesting and challenging change as well.
And to finish, survived up to level 20 with 90,842 points.