The objective of Tetris, like so many other single-screen video games, is to stay alive for as long as possible while scoring as many points as you can. The game begins with one of seven differently shaped blocks falling down the playfield. This block is followed by another, and another. Each of the seven block shapes is composed of four small squares.

You manipulate these blocks, which fall one at a time, by moving them left and right and rotating them as they descend. One randomly selected block after another falls down the screen, and you must arrange these blocks to prevent them from stacking up to the top of the play field.

Every time you fill in an unbroken horizontal line across the play field, that line disappears, clearing the way for more blocks. With enough practice, you will figure out how to fill in double, triple, and quadruple lines with the drop of a single block, maximizing your score. By not allowing the blocks to reach the top of the screen, you will reach higher and higher levels, meaning an increase in the rate at which the blocks fall.