A very fun game for puzzle fans. One small problem that seems to reoccur is the spinning being bad for your sight. I didn't play for very long, noticing this, but I still had a small feeling of my screen spinning even after leaving the game. And I only went to level 4.
You could fix the spinning problem, by having an option to only spin to the side you are playing from. Have it be an easier difficulty or something. Then you could also add a harder difficulty where there is zooming involved or something.
One other thing that you could fix is the placement of blocks when you clear some of them. In traditional tetris the blocks drop into position after clearing the line(s). However, since simply dropping them might send them off the screen, thus resulting in game over, I suggest you have them move one square "inward" diagonally.In a grid of 3x6, if you have a block at 1,1 and another at 2,6 when you cleared a line, the block at 1,1 would move to 2,2 then to 3,3 where it would settle on the base while the block at 2,6 would move directly to 3,5 and sit there, again having hit the base. This diagonal movement would ensure that the blocks always moved toward the center and would add more strategic thinking to how you position the blocks.
Other than that (and possibly some music selections) I think this was a great game idea and was executed well. I hope to find Quatris2 (squared?) soon.