DDTank 2 is a free to play social unique fighting MMO game which has a heavy social side. It is not just about battles. DDTank 2 has unique features like avatar weddings to adopting pets and farming. The game itself is similar to Gunbound and is able to run in a browser with no need for any downloads. You must align your shots properly and take into account wind and elevation and remember there is always something to blow up.
Follow the in game tutorial.