How 97 Copies of an Unreleased Version of Super Mario Bros. Duck Hunt Were Discovered in a Wisconsin Warehouse

July 29, 2026 - 20:11

When Jason Ganos agreed to help sell an old box of Nintendo cartridges from a Wisconsin warehouse, he assumed they were just used copies of common games. He had no reason to think otherwise. The box was dusty, tucked away in a corner, and looked like it had been sitting there for decades. But when he opened it, he found something no one expected.

Inside were 97 copies of an unreleased version of Super Mario Bros. and Duck Hunt. These were not the standard cartridges that millions of people played in the 1980s. They were test copies, likely used by Nintendo for quality control or retail demonstrations before the final game hit store shelves. The labels were different. The circuit boards inside were different. And most importantly, the software itself contained code that had never been seen by the public.

Ganos, who runs a retro game store, quickly realized this was not a routine pickup. He contacted collectors and preservationists to verify the find. Experts confirmed that these cartridges were authentic prototypes, possibly from a short run made for a specific retail chain or a trade show. The warehouse had once been used by a company that distributed Nintendo products, and somehow these test units were never sent back or destroyed.

The discovery sent shockwaves through the retro gaming community. Collectors and historians scrambled to document the cartridges before they were sold or scattered. Some of the copies have already been sold to private collectors for thousands of dollars each. But for Ganos, the real value is not the money. It is the chance to preserve a piece of gaming history that should have been lost forever.