Tetris

Across its numerous versions, Tetris generally has a consistent puzzle video game design. Gameplay consists of a rectangular field in which pieces consisting of four connected blocks, called tetrominoes, descend one at a time from the top-center. During the descent, the player can move the piece horizontally and rotate it until it touches the bottom of the field or another piece. The goal is to stack the pieces to create horizontal lines of blocks.

When a line is completed, it disappears and the blocks placed above fall by one row. The speed of the descending pieces increases as lines are cleared. The game ends if the accumulated pieces in the field block other pieces from entering the field, a process known as "topping out". Common mechanics among Tetris versions include the queue (viewing the pieces that are next to appear), soft drop (increasing the descent of the piece), hard drop (instantly placing the piece as far down as it can go), and holding (reserving a piece for later use).

In the 1980s, Alexey Pajitnov was a Soviet speech recognition and artificial intelligence researcher at the Dorodnitsyn Computing Center of the Academy of Sciences who operated an Elektronika 60, a Russian clone of the PDP-11 computer. While at the center, he developed at least twenty types of video games in his spare time. Pajitnov bought a pentomino puzzle set from a store and played with it in his office, and he became inspired to adapt the puzzle game to the computer. On the Elektronica 60, Pajitnov experimented with different pentomino configurations.

He felt that the game would be needlessly complicated with pentominoes and their twelve different shapes, so he scaled the concept down to tetrominoes, using seven different shapes. Pajitnov programmed Tetris using Pascal for the RT-11 operating system on the Elektronika 60. Because the Elektronika 60 had no graphical interface, Pajitnov represented the pieces using bracket and space characters. Afterward, he programmed the basic mechanics, including the ability to flip tetrominoes as they fell in a vertical screen and the clearing of lines.

According to multiple sources, Tetris is the best-selling video game of all time, with over 520 million copies per The Tetris Company. This sales figure is likely compiled from multiple versions of Tetris into one composite number. The majority of sales originate from paid mobile downloads; in April 2014, Rogers announced in an interview with VentureBeat that Tetris totaled 425 million paid mobile downloads and 70 million physical copies. The BBC disputes the claim of Tetris being the best-selling video game due to differences between the versions, including on mobile platforms, arguing that Minecraft (2011) is the true best-selling video game of all time. The most commercially successful version is the Game Boy version at 35 million copies sold.

Tetris has garnered accolades and awards since its initial commercial release. The Spectrum HoloByte version won three Software Publishers Association Excellence in Software awards in 1989, including Best Entertainment Program and the Critic's Choice Award for consumers. Macworld inducted Tetris into the 1988 Macworld Game Hall of Fame in the Best Strategy Game category. Macworld praised "the addictive quality" and said its "simplicity is bewitching", and Compute!

Due to Rogers and Nintendo's belief in its potential for mass appeal, Tetris was the pack-in game and the primary game promoted for the Game Boy in the United States. The resulting public anticipation led Tetris to become the Game Boy's main draw, with many, including non-gamers, buying the Game Boy specifically to play Tetris. It contributed to both the popularity of Tetris and the Game Boy, with the bundle selling out its initial run of a million copies shortly after release. This success established Nintendo's dominant position in the handheld gaming market, setting a standard that competitors struggled to replicate. Several writers credit Tetris and Pokémon Red and Blue (1996) for the Game Boy's longevity, as it would not be discontinued until 2003.

Tetris is influential in the genre of puzzle video games. Commentators have considered Tetris an early example of a casual game. com credits Tetris for establishing a market for puzzle video games with universal appeal. Various common elements of puzzle games, such as managing pieces over a fixed screen, originated from Tetris, and multiple clones have been created to replicate Tetris's popularity.