Super cool take on tetris! The concept is fun an the clear animations were incredible!
I think you should make it so that placed pieces fall down after the blocks underneath them are destroyed - this would allow for some really sick puyo-puyo styled chain reactions! And I would recommend making it so that you lose control of your blocks once any of them activated - as it is right now you can use the same shape to clear a ton of different blocks one by all over the whole board. Lastly the game felt a bit too easy - I think you should make the fall speed ramp up faster.
Aside from these 3 points the game is already really great an has a lot of potential! :D