New Glitches Uncovered: Speedrunner Kosmic Discovers Hidden Levels in Super Mario Bros. The Lost Levels

Super Mario Bros.

The Lost Levels, known in Japan as Super Mario Bros.

2, has long held its place as one of the most challenging and iconic platformers in Nintendo’s storied history.

Decades after its original release on the Nintendo Entertainment System (NES) and subsequent appearances on platforms like the Nintendo Switch and the eShop, new discoveries continue to fascinate longtime fans and the speedrunning community alike.

This legacy was recently expanded by Kosmic, a prominent figure in Mario speedrunning, who successfully accessed and completed a sequence of glitched levels in Super Mario Bros.

The Lost Levels—levels that, until now, no one had claimed to have fully beaten.

The feat was highlighted in a detailed video posted by Kosmic, whose expertise has continually pushed the boundaries of what players believed possible within classic Nintendo titles. The process by which Kosmic unearthed these new pathways provides valuable insight into level design and coding practices from the early days of Nintendo.

In Super Mario Bros.

1 and The Lost Levels, the level and world counter is determined by the object the player uses to finish a stage.

When Mario grabs the flagpole at the end of a course, the second digit of the counter increments, while collecting the castle axe increases the first digit.

This under-the-hood mechanic explains unique level identifiers, such as '1-6', familiar to fans of ROM hacks and glitch explorations. Much like the infamous 'Minus World' in the original Super Mario Bros.—a hidden area accessible due to quirks in the game's code—Kosmic used similar page manipulation techniques to access these anomalous zones in The Lost Levels.

He reset the current world counter while preserving the level number, allowing him to move beyond the traditionally capped World B and into higher, glitched levels such as B-5 and ultimately B-M.

According to Kosmic’s analysis, after the counter reaches its limits, the second digit transitions into letter characters, creating a series of unpredictable and visually striking stages. What is especially notable in Kosmic's discovery is the fact that no external modifications, such as GameShark devices or unofficial patches, were utilized.

The methods employed rely entirely on skillful manipulation of the original game, showcasing the depth and resilience of Nintendo’s classic code—even decades after release.

While the levels themselves recycle design elements from other worlds, their unusual presentation and the technical prowess required to reach them make this a landmark achievement in the Super Mario Bros.

speedrunning community. As Super Mario Bros.

The Lost Levels continues to be re-released on modern hardware platforms like the Nintendo Switch through the eShop, these discoveries only add to the game’s enduring mystique.

For enthusiasts of classic Nintendo platformers and glitch hunters alike, Kosmic’s achievement serves as a reminder that even the most thoroughly-analyzed titles can still hold secrets, waiting for the next ambitious player to uncover them.

Nintendo Switch Nintendo Mario NES Switch Super Mario Xbox Series X|S Super Mario Bros Kosmic Super Mario Bros. The Lost Levels Mario Bros game development Xbox X|S Super Mario Bros. The Lost Levels Super Mario Bros. 2 Japan eShop