I am one of the developers of FallingBlocks, a game with the same gameplay concepts as Tetris.
This night, I have received an email warning that my game was suspended from Android Market due to a violation of the Developer Content Policy. When I received the email, I already imagined that it had something to do with it being a Tetris clone, but besides having the same gameplay as Tetris, which i believe cannot be copyrighted, the game uses its own name, graphics and sounds. There's no reference to "Tetris" in our game.
I have emailed Google asking what is the reason for the application removal. Google promptly answered that The Tetris Company, LLC notified them under DMCA to remove various Tetris clones from Android Market. My app was removed together with other 35 Tetris clones.
So, I checked online on various sources, and all of them say that there's no copyright on gameplay. There could be some sort of patent. But besides not having a patent, which would last 20 years, so it would be over on 2005.
It's a shame that The Tetris Company, LLC uses its power to stop developers from creating good and free games for Android users. Without resources for a legal fight, our application and many others will cease to exist, even knowing that they are legit. Users will be forced to buy the paid official version, which is worse than many of the one available for free on the market.
Users from other countries, which is my case in Brazil, won't even be able to play the official Tetris, since Google Checkout doesn't exists in Brazil, so you can't buy paid applications from Android Market in these countries.