Tetris is a simple puzzle game for all age groups. The play control is excellent and the game is very easy to pickup and play. The object is simple just make as many solid lines out of the falling blocks as possible.  A Tetris is basically when you clear 4 lines at once.  You score points for single, double, triple and Quadruple lines.  The Gameboy screen and NES Tetris games would only let you get 2 Tetris's at once before you reached the ceiling causing a game over.