Tetris 99 is a multiplayer puzzle game in which 99 players play against each other at the same time, with the aim to be the last player remaining. As with the traditional Tetris formula, players rotate and drop shaped bricks known as tetrominoes onto a board. Players can clear tetrominoes by completing rows across both sides, whereas players will lose if tetrominoes overflow off the top of the board. As with normal Tetris rules, players have the option to store a tetromino piece to swap out at any time. By clearing multiple lines or performing continuous line clears in a row, players can send "garbage" to other players, which will appear on their board unless they can quickly clear lines in response. More garbage can be sent by completing combination moves in succession of making a "tetris" (matching 4 lines at once) or performing a "T-spin" (squeezing the T-shaped tetromino into a position it would otherwise not fall into by rapidly rotating it).