During late 90’s web games as we know them did not exist.
Read more information at the official page, where you can play Tetris.
I have to say, at the moment the game is giving me an error, but yesterday I managed to play from another computer.
It’s still in a very early stage of development and may change a lot in the versions to come.
There is an interesting game (with a detailed tutorial) you can play: a Money Idol Exchange clone called Mechalchemist