Sonic the Hedgehog Megamix

Sonic the Hedgehog Megamix (commonly shortened to Sonic Megamix or Sonic 1 Megamix) is a 2005 overhaul ROM hack of 1991's Sonic the Hedgehog for the Sega Genesis, developed by Team Megamix; the game was first initially released on May 31, 2005, as part of the 2005 Sonic Hacking Contest, with updates in the following years. The game takes place 15 years after the events of the original Sonic the Hedgehog with Eggman back on South Island with a Chaos Emerald, with Sonic trying to stop him once again.

The latest stable release was on June 30, 2007, referred to as release 3.0; an unstable version titled 4.0b was leaked on August 13, 2008, and another later build unofficially titled 5.0a was leaked in 2014. In 2016, it was announced by the project leader Stealth that Megamix had officially been cancelled due to the rest of the team leaving the project for personal reasons and other projects, although he stated that he intends to bugfix the last build and release it alongside the source code; Stealth would later go on to be a developer for the official Sonic game Sonic Mania, released in 2017.

The hack has gained notoriety for its sheer amount of content compared with the original, and is one of the few known Sonic ROM hacks to make its way onto cartridges in Russia.

Development
The project was originally lead by Dustin Wyatt, known online as Tweaker or Sonic Tweaker, but following the release of evidence of pedophilia and bestiality, Sonic Tweaker was removed from the team with Simon Thomley, known online as Stealth, taking over as the leader. In 2007, the game was ported to the Sega CD to take advantage of its expanded storage and CD audio capabilities; version 3.5 was the last Genesis build made. The project would be temporarily cancelled in 2008 for three days, although it took several months for him to reveal it.

In 2014, the Team Megamix website suffered a leak by a hacker attempting to spite Sonic Retro (despite Megamix not being an official Retro project), which saw the leaking of a build made in mid-2011; this build quickly spread online, in which fans had called the version 5.0 final due to its various differences, despite the build being very incomplete. Stealth was reportedly upset with the leak, but decided to unofficially 'release' it anyways with them stating that it should be titled 5.0a, or 5.0 alpha.

In 2016, Stealth announced the official cancellation of Sonic Megamix; according to him the rest of the group had left for personal reasons and to work on other projects other than Megamix; he also stated in the post that he intends on fixing up the last build for a final, "not so sloppy" release, alongside its source code for anyone wanting to make a Megamix-like hack, although he also stated that it would take awhile. Stealth would also later be confirmed working for Sonic Mania, released in 2017 by Sega.