Awesome idea.
Very well thought out idea, although I kept getting mixed up which button turned which direction (this resulted in a lot of mistakes near the end, but I get this way with all dual rotation games, usually. Except the original tetris for some reason (all remakes however...), and I got pretty bored after awhile (I would have preferred the tetris mechanic where a full line clears and the blocks drop faster and faster over time. Filling the board one block at a time was less than compelling), and I just kinda gave up near the top where you really don't have much of a chance to change the piece how you want and it'd already been perfect until then anyway. I'm not sure if those are design flaws per se, but for me at least, a few changes might have made this more compelling.
Still the most interesting and innovative idea I've seen in flash games in quite some time, regardless. I love napkin ideas :P. It's how I came up with Proximity. I'll have to check your site out sometime.