Super Mario Bros., as we know, is now over 40 years old – so you'd expect every secret contained within the game's code to have been uncovered by this point.
However, as reported by Polygon, a new glitch was recently found in Super Mario Bros.: The Lost Levels which caused quite a kerfuffle. Twitter user @LuigiSidekick discovered that The Lost Levels crashes during a castle level – something which might not sound all that exciting until you take into account that crashes don't necessarily happen randomly; they're an indication of glitches or exploits within the code which can potentially be used to the player's benefit.
A little more digging revealed that Arbitrary Code Execution (ACE) is possible in The Lost Levels – this effectively means the player can 'reprogram' the game in real-time during gameplay. As you can imagine, this discovery got people wondering if the same was true of the original Super Mario Bros., upon which The Lost Levels is derived.
Kosmic, a leading Super Mario Bros. speedrunner, pulled together a research team to pull the original game apart, and while the setup is incredibly complex, ACE has finally been found in the game.
Speaking to Polygon, Kosmic is quick to stress that, in its current form, the glitch's impact is quite limited – in fact, from a speedrunning perspective, it takes longer to set up ACE than it does to beat the game normally.
However, what makes ACE so interesting is that it could lead to other discoveries with a greater impact.
As Kosmic tells Polygon:
"I guess it's 'for fun,' but it's more so about the achievement of making it possible and solving it. And for example, if you want, you can now access not just the Minus World, but any world or level you want. With no hacks or cheats. It's a glitch that makes anything possible."