While you might have completed the game a handful of times since its release over three decades ago, there are some folks out there who are hugely dedicated to completing and competing with finishing the game as quickly as possible. Some have ultimately played through hundreds or even thousands of times. Did your last playthrough take an hour-and-a-half? That's cute, because many speedrunners have whittled that down to a mere 5 minutes. You can see an example of the latest world record below, performed by Brad Myers, aka: darbian.
As the chart below highlights, despite the game's age, people have managed to continually improve upon their times. Ten years ago, ~5m 5s was the best recorded time, whereas over time, as more and more glitches were discovered, valuable milliseconds have been shaved off to bring us to the magical 5 minute mark.
In a very specific example of how these discovered glitches can help, one person uncovered, after poring through the game's code and memory store, that certain flagpoles at the end of levels could be activated through the bottom brick, rather than anywhere above it. Despite it being very difficult to even notice the difference as a viewer, exploiting that glitch multiple times throughout a speedrun helps save enough time to enable gamers, like darbian, to set new world records.
Want to know how some of these glitches work? Look no further than these two videos:
Understanding how these glitches work and actually pulling them off are two very different things, so don't feel disappointed if you can't manage it without a lot of practice. When an instruction is specific and precision to the point of "Jump and land on the first pixel of the 2nd stair from the top, and don't hold B while doing it", it's only going to be pulled off by very dedicated speedrunners.
Even if you're not a speedrunner yourself, it's rather exciting to watch these runs be pulled off. Some might even call them a work of art. For us regular folk, there's a big question lingering: just how much faster can a Super Mario Bros. speedrun get? If it took an entire decade to improve a run by 5 seconds, it does seem like we're coming to a point of diminishing returns for all that effort. However, the momentum behind finding new glitches isn't slowing down, so we could very well be surprised. Let's hope so!