As Mario authority Kosmic explains in a recent YouTube video, the games are structured as “areas” made up of individual “pages.” When you approach a warp pipe, the game stores the destination area’s and page’s values in memory.
Kosmic notes that if a warp pipe is entered before the game has finished loading the intended warp destination, the engine will send Mario to whatever destination is currently stored in memory—often nothing more exciting than the normal exit for that level. But if you enter a pipe while moving so the screen scrolls as you descend, the warp destination can load after you’ve already gone in. That forces a black‑screen transition, and when play resumes Mario will always begin on page zero—sometimes with unexpected results.
In these corrupted stages, underwater zones can become standard platforming levels; visual artifacts multiply until the screen is layered with unintelligible sprites and numbers. The example above looks like a hallucinatory, code‑laden landscape—Kosmic even manages to progress through parts of some of these stages by recalling the original layouts.
So, 39 years after the Japanese release of Super Mario Bros. 2, a kind of Minus World for that title has finally been demonstrated. These stages have quietly existed at least since Super Mario All‑Stars shipped, and they remain reachable today—if you can perform the precise, speedrun‑grade maneuvers required to access them on an old SNES cartridge.
Source: gamesradar.com
