Ah, this game. I never understood it until I was about 7, then I started playing any Tetris I could almost non-stop. Anymore, I play Tetris just to exercise my mind and reflexes.
Interesting note about this song, while most of the 1-10 stage songs run at 145 beats per minute (Except Egypt, which is 147), this song runs at 143 beats per minute. Just thought that would be an interesting tidbit.
The first tetris game I played was for the gameboy, tetris plus was the second, but when I played tetris plus on the PS1 as a kid, I always used to think that the professor was Mario, mainly because he was on the gameboy version of tetris whenever you play multiplayer, ah the days of using a link cable.