Original Tetris

When a non-enthusiast refers to "the original Tetris", it is likely that they are referring to one of the games below. All of them garnered large amounts of recognition and caused a national/worldwide phenomenon early in the history of the game.

• Tetris (Game Boy) Arguably the most famous version worldwide.
• Tetris (NES, Nintendo)
• Tetris (Sega) Japan only; caused a sensation in arcades one year before the debut of the Game Boy version. Often referred to as the one "with the monkey".

Original in the strict sense of the word

The "original" version in the strict sense, however, would be:

• Tetris (Electronica 60)

as it is the world's very first implementation of the Tetris game ever to be developed on a electronic device.

• Tetris (IBM PC)

the IBM PC version is also notable as although it is not the first ever, it is the first version to run on a platform popular in Western countries.