Hackers discover how to reprogram NES Tetris from within the game

Earlier this year, we shared the story of how a classic NES Tetris player hit the game's "kill screen" for the first time, activating a crash after an incredible 40-minute, 1,511-line performance. Now, some players are using that kill screen—and some complicated memory manipulation it enables—to code new behaviors into versions of Tetris running on unmodified hardware and cartridges.

We've covered similar "arbitrary code execution" glitches in games like Super Mario World, Paper Mario, and The Legend of Zelda: Ocarina of Time in the past. And the basic method for introducing outside code into NES Tetris has been publicly theorized since at least 2021 when players were investigating the game's decompiled code (HydrantDude, who has gone deep on Tetris crashes in the past, also says the community has long had a privately known method for how to take full control of Tetris' RAM).

But a recent video from Displaced Gamers takes the idea from private theory to public execution, going into painstaking detail on how to get NES Tetris to start reading the game's high score tables as machine code instructions.