The Sonic 1 Beta Hoax

This is an early Sonic hack of Sonic 1 (Sonic The Hedgehog 16-bit) by
Cyan Helkaraxe in 1999.  For testing purposes, here is a snippet from
Sonic Retro's wiki:

Sonic 1 Beta Hoax is a ROM hack created by Cyan Helkaraxe in 1999. When it
was first released, it was purposely not described as being a hoax. As a result,
many individuals mistakenly thought for a time that it was a legitimate prototype
of Sonic the Hedgehog for the Sega Mega Drive.

History

In 1999, Cyan Helkaraxe wanted to stir up more interest in Sonic 1 among the
Sonic community. He decided to do something which had never been done at that
time: create a ROM hack. The resulting hack would become known as the
Sonic 1 Beta Hoax.

Cyan set to work on the Sonic 1 ROM, researching its internal workings
primarily by a trial and error process, since there was absolutely no
documentation on Sonic 1 available at the time. His goal was to create
a hoax prototype - a game that mimicked the behavior of a "genuine" Sonic
1 prototype.

In May 1999, Cyan released his hack to Simon Wai's Sonic 2 Beta page. The
ROM was deliberately not listed as a hoax; rather, it was released under
the title "Sonic 1 beta?".

The release of the hoax prototype stirred up more interest in Sonic 1, and
when it was identified as a hoax, Andy Wolan invited Cyan to the Sonic Stuff
Research Group for his work in creating the ROM hack.