Like everyone said, this is a really fun and unique concept for Tetris given the theme. Also like everyone said, however, it can be a little frustrating when you don't have the right pieces, and the reroll feature can only get you so far. Rotating the pieces might help.
For further feedback, I wonder if you can think about what happens to the pieces you remove aside from simply disappearing outside the screen. Maybe you can save those one at a time and you'd be allowed to rotate it and use it to remove additional pieces. Or more it's just something aesthetically fun. Just a thought.
If you do plan to develop it more, I am eager to see what comes out of it. Great work.