Sonic the Hedgehog (1991) prototype discovered

Determined to start 2021 off on the right foot; infamous scene member 'drx', along with The Cutting Room Floor have uncovered what is long thought to have been lost to the ages.

While a number of Sonic the Hedgehog 2 (1992) betas and prototypes, including the famous Nick Arcade build have been floating around the internet since 2006; and then more recently in 2019 we saw the surprise discovery of a Sonic the Hedgehog 3 (1994) prototype - it's long been thought that any and all early builds of Sonic's first outing on SEGA's 16-bit machine would never be found.

Although plenty of early show floor demos and VHS tapes have made their way onto the internet which show glimpses of early Sonic 1 footage and a bevy of fan made hoax ROMs exist - until last night this is all we had to show for SEGA's first entry in the Sonic the Hedgehog series.

Although an exact build date of the ROM is unknown, it's thought to be from mid to late development of the title. A number of zones are near complete while a couple including Labyrinth and Spring Yard Zone look quite different from the final product.

Here is a list of key differences that has been compiled by members of the scene:
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Normal SEGA startup - no SEGA choir
No 'Sonic Team Presents' screen
Many level layout differences
Many level art differences
Object placement differences
Large rolling ball in GHZ
LZ is missing water entirely
UFO's present in MZ sky
Slower lava in MZ
Missing boss in MZ
Some instrumentation differences
Special stage ring does not appear at end of the level
Spring Yard Zone is known as Sparkling Zone
Star Light Zone is very unfinished
Scrap Brain Zone shows as Clock Ork Zone
COZ is very unfinished
Splats (enemy) is present and functional via debug

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https://hiddenpalace.org/Sonic_the_Hedgehog_(Prototype)

Sonic the Hedgehog (1991) prototype discovered | GBAtemp.net - The Independent Video Game Community