Tetris is a series of video games originally designed and programmed by Alexey Pajitnov in the Soviet Union in 1984. The original Tetris game is also the first game in the Tris series, of which Tetris is a sub-series.
The gameplay consists in stacking the falling shapes, called "Tetrominos", each composed of four blocks, trying to leave the least gaps as possible, since if a full line of blocks is created, it is cleared and awards points, while if the blocks reach the top of the field it's Game Over.
Since they're all puzzle games, most of them don't have any kind of storyline, so it might seem not appropriate to consider it a fictional series, however some of them do have a storyline with characters interacting with the tetrominos, such as Tetris Plus, and others feature the Tetrominos as living beings such as Kids Tetris, so we can say that at least at some point, the Tetris series told a story, making it a fictional series.
