Beyond the visuals, the ROM is a fascinating case study in game feel. The physics engine in the beta builds is notoriously slippery. Mario accelerates faster and stops with less precision. For a modern speedrunner, these differences are profound. Glitches that have been patched out in the final version—such as specific collision oversights or blaster jumps—are rampant here.

the E3 build is officially dated May 14, 1996. It provided a polished, playable demo that allowed attendees to explore the castle grounds and specific levels like Bob-omb Battlefield Whomp's Fortress to get a "real feeling" for the new 3D movement. Key Differences from the Retail ROM

Preservationists caution: this is not a polished demo. It’s a trade show prototype meant to run for five minutes under supervision. But for those willing to explore, it’s like finding the blueprint for a cathedral — rough edges, erased pencil marks, and all.

The E3 1996 build was roughly 80% complete and very close to the final product, but featured several distinct "beta" elements: HUD and Graphics: