And here i thought i've seen them all in terms of new tetris ideas. The mechanics function really well. There were about 3 aha moments for me when i realized how the mechanics changed my normal understanding of tetris and those were the highlights for me.
I would have wished for more visual clarity between the background and the playing field and a bigger size of it as well. Also the music didn't loop so i was left with silence after the song ended.
I quit at about 19/30 lines but i think i would have kept playing if the bar was set a bit lower for the first level.
Anyway good job!