It wasn't until late 2020 that an individual by the name of Buckaroo found a cartridge containing this prototype, and released its contents through Hidden Palace (on New Year's Day) for gamers to enjoy. Along the way, there were also a few ROM hacks created as attempted guesses to what such a prototype would look and play like (including Sonic 1 Beta Hoax, and Sonic 1 Beta Remake). During the time before this build surfaced, prototypes of all the other 16-bit Sonic games were discovered, dumped, and shared with the public. Long considered a holy grail by the Sonic community, a Sonic 1 prototype was sought after for around two decades. It also features a plethora of interesting content that was previously only seen in grainy magazine screenshots and raw gameplay footage, like the rolling checkered boulder in Green Hill Zone, the UFOs in Marble Zone, and Spring Yard Zone when it was still called 'Sparkling Zone'.

This build reveals a game that was originally tuned more for traditional platforming and exploration rather than for speed, which would eventually become the hallmark of the Sonic series. Many stages cannot be completed due to the lack of signposts and bosses some (like Clock Work Zone Act 3 and Final Zone) haven't been started at all, or are obvious placeholder designs (like the Special Stage). It depicts the game midway through development. A prototype of Sonic the Hedgehog was released by Hidden Palace at Midnight (GMT) on January 1, 2021.

Sonic 1 beta sprites