When I made a game crash through a bug before I did not consider myself beating the game, that is why I have or had difficulties understanding. I suppose the difference is making it crash through playing as many levels, for example, as possible.
Also the Tetris player here (edit: arguably) isn't "exploiting" a bug. The game just literally hits a limitation that can only be hit via extended and nearly superhuman play
I think most "serious" Tetris players can get to 30 easily in a short amount of time, right? Like 15-20 minutes? It'd be hard to think of that as a legitimate "ending."
Whereas a run to level 100+ or whatever for this kill screen is a major achievement. Took people 30+ years to get there.
I don't know, though. It's all subjective. If you want to think of a hypothetical lvl 30 crash as a "kill screen" or "ending" then hey... go for it.
So, this was the first person to encounter the "bug" (hardware limitation). But, future players may try to hit that point faster, with a lower/higher score, or other combinations of game state to beat the game in a "better" (more interesting) way.
In a game with no human-authored intentional "win state", one reasonable definition of "beating the game" is "reaching a state that no other player is able to surpass". If the game crashes at a certain point, then reaching that crash is a viable state that fits that definition.
Pushing limits in games is fun.
I've never played competitively, but I remember well my own excitement as a child whenever I managed to trigger a glitch (such as getting enough bonus lives to overflow the lives counter on Commando on C64, which was pretty simple but still was very exciting the first time it happened).