Tetris is a casual version of the classic Tetris block-puzzle game. As with the original, the player's goal is to earn the highest possible score by creating 10-block horizontal lines for as long as possible across 10 levels.
The screen displays a vertical blue-gray playfield with a textured light-blue right side area. Black-outlined, colored tetrominoes of the polyomino category of block shapes drop one at a time from the top-center of the screen. The game displays a preview of the next shape to drop in a rectangular preview pane at the top-right corner.
The player directs the shape as it falls. They can rotate it into an optimal position and slide it left, center or right. They must drop each shape with care to interconnect the shapes without creating gaps. Every time they perform this task successfully and the shapes form a line, the game removes the line and assigns points.
Tetris speeds up the drop of new shapes over time. It also manipulates the player into believing that they've finished placing a shape to cause errors. If the player thinks the shape has stopped moving and start to reposition the next shape, the game sometimes shifts the previous shape into a suboptimal position. The best way to prevent this scenario is by not using the controls at all until the next shape appears on the screen.