AFAIK, gameplay cannot be copyrighted, but could be patented. Besides never being patented, patents last for 20 years, and the game was made on 1985, the patent would be over by now.
Why cloning a 25 year old game? The answer is simple. People want to play it. In fact, at first i didnt find any satisfactory Tetris on Android market and decided to make my own. Then i thought it was good and put it on Android Market.
Besides some lousy ads, i dont make money with the game.
I could file a counter-notice, but that could lead The Tetris Company LLC to a law suit against me, and i dont have time or money for that.
The game is available on our website, if anyone wants to download.