The goal is to get as many blocks down as possible. The game ends when a block can't go below the top of the game. If there is a horizontal line that has no empty squares, then that line is removed.
All blocks of classic tetris consist of 4 squares, but this game also has blocks that consist of 1, 2, 3, or 5 squares. Also, classic tetris is 10 columns wide, but this game is 12 columns wide by default.