Hacking the game reveals an unfinished, but playable two-player competitive mode in the game's code.

Playing game B on speed 9 and reaching height 5 will provide a sequence of Nintendo characters celebrating. These characters include Mario, Luigi, Peach, and Bowser from Super Mario Bros., Donkey Kong, Link from the Legend of Zelda, Pit from Kid Icarus and Samus from Metroid.

An airplane and a helicopter can be found amongst the game's ending sprites. They never show up in any endings, but otherwise work perfectly and can be made to appear via hacking.

In 2019, a meme image was posted by Twitter user Vecchitto showing a fake page from the Tetris manual giving the Tetrominos their own names:

• J is "Orange Ricky"
• L is "Blue Ricky"
• Z is "Cleveland Z"
• S is "Rhode Island Z"
• I is "Hero"
• T is "Teewee"
• O is "Smashboy"

Later in the same year, these fake names would appear on an episode of Jeopardy!, mistaken for official Tetris names. Despite being incorrect, the player given the question still answered correctly.

Notably, the hoax manual mentions the colors of the J and L blocks, which were not established at the time, with every block's color palette being based on the level instead of the shape.

In December 2023, a 13-year-old boy named Willis Gibson from Oklahoma became the first known person to "beat" the NES version of Tetris. At level 157 (which in itself was a world record), he reached the game's "kill screen", a feat only accomplished previously with machine assistance. A video of his victory was uploaded to his YouTube channel "Blue Scuti" on January 1, 2024.