In the stream, he mentions it being tetris gym. And the options screen confirms it. Tetris gym is accepted by the community as faithful in all the ways that matter for being allowed to be used for records. The main thing it patches out are the crashes. It also patches in the ability to run the game as either ntsc or pal, as that makes a huge difference in nes tetris. And critically in dogplayingtetris’s case it allows the ability to disable pausing the game. His controller is well worn, so his start button goes off randomly on it’s own.

This article actually seems pretty uninformed, probably just in a rush to be first to post. Their explanation of the crashes is wrong, and they seem unaware that the speed is actually the same once you pass the first initial batch of levels that used to be considered the “human playable” levels. Of course, not anymore.

Also no mentions of literally the biggest challenge faced, level 235 and it’s need to clear 800 lines instead of the usual 10 to pass it. So it’s 80 levels baked into one. And it’s one of the top 5 worst color schemes for readability to boot. Like, if the game was actually designed to be played this way it would almost like it was made as an intentional final boss, lol. Instead of just being a result of a look-up table eating code that is nowhere near the “table”, and is instead on the floor, or the nearby garbage can… hehe

Probably Tetris Gym?

EDIT: The “kill screen” in NES Tetris is just the game getting too fast for most people to keep up. Then there’s some bugs that can crash the game in later levels, but Tetris Gym fixes these bugs. So you “just” have to be good enough to play Tetris for long enough at insane speeds.

I’m just waiting for aGameScout to drop a video on this one. He’s been doing excellent deep dives on every Tetris milestone