There are two issues with the actual Flash game (Tetris) I'd like to bring up. One is a suggestion, the other is a possible bug.
1. Suggestion: On the introduction screen (after the Loading), there could be a way to bypass it and go straight to the game. I know it only lasts a few seconds, but when you're on a roll, trying to get the next high score, it's seconds of agony waiting for the game to hurry up and frickin' start.
2. Problem: I don't know the level number, but it's the one that starts with a single line going all the way across the screen, closer to the top, with a two-block-wide hole near the middle. If you get a zig-zag-shaped piece right away, and fill in the hole in that line, the line does not disappear right away. The line does not disappear until you drop the next piece. It doesn't matter where you drop the next piece, and obviously, you can't make a solid line with it, but as soon as you drop it, the line you made with the first piece then disappears. I hope you can understand what I'm saying.