Too similar...
Personally, I think game is too similar to Tetris to be considered a new game... it's nice that you include new pieces, but the controls were very sluggish, there was no music, and sound effects were minimal. Also, the splash is very misleading, as the large button immediately underneath "Start," which I assumed needed to be clicked in order to start, just opened a popup window. You already link to the same place with your "High Scores" link, so either change the action of the large button to start the game, or just remove it entirely. Additionally, I don't appreciate having the "IQ Test" link included, as A) it opens another popup, B) isn't related to the game and C) isn't from the same server that the high scores are hosted on, so I assume it's not even yours. I have a problem with shameless promotion of someone else's site in a Flash.
Add in some originality (more than different pieces), some music, and make the controls more responsive.