List of unofficial Sonic media

Unlicensed developers and fans have created unofficial Sonic media, especially video games, relating to the Sonic the Hedgehog franchise. These products include video games, video game mods, ROM hacks, and animations. Due to the popularity of the franchise, some of these unlicensed products have received critical attention.

Video games
The following are all original games based on the Sonic series.
 * Green Hill Paradise Act 2 is a 3D Sonic game built by Daniel "SuperSonic68" Coyle and other collaborators with the 3D Sonic Games Development Kit. This game gained notability for receiving a positive response from Sega.
 * Sonic Utopia is an open-world, 3D Sonic game early in development with a four-person team as of late 2016.
 * Sonic: Before the Sequel is a 2D Sonic game set in between the events of Sonic the Hedgehog and Sonic the Hedgehog 2. The game received wide critical praise for its faithfulness to earlier titles, and two sequels, Sonic: After the Sequel and Sonic Chrono Adventure, were later developed and released.
 * Sonic Dreams Collection is a parody Sonic game presented as a Dreamcast development kit containing cancelled Sonic games. The game caught media attention for its bizarre nature and its intent to lampoon the Sonic fandom.
 * Sonic the Hedgehog 2 HD is a high-definition fan remaster of Sonic the Hedgehog 2 in development. The final version is planned to feature additional stages and the ability to play levels as Knuckles the Echidna.
 * Sonic Fan Remix is a 2.5D Sonic game created in Unity that features reimagined levels from past Sonic games.
 * Sanic Ball is an online parody Sonic racing game inspired by the popular "Sanic Hegehog" internet meme.
 * Retro Sonic is a 2D Sonic game created by Christian Whitehead. It is the first game to use the Retro Engine (the engine used for the 2011 remaster of Sonic CD), and later merged with two other Sonic fangames, Sonic Nexus and Sonic XG, to form Retro Sonic Nexus.
 * Sonic Robo Blast 2 is a 3D Sonic game that uses a modified version of the Doom Legacy engine and has been in development since 1998.
 * Chao Resort Island is a fangame for Microsoft Windows and macOS, based upon the Chao-raising minigames in Sonic Adventure.
 * Sonic World is a game heavily based upon the Sonic Adventure titles and Sonic Heroes. It features over thirty playable characters and the ability to make Heroes-style teams, as well as remastered levels from various Sonic games.
 * Sonic Z-treme is a homebrew Sega Saturn game that aims to recreate concepts from the canceled game Sonic X-treme using original code. It can be run on real Saturn hardware if burned to a disc.

Unofficial ports
The following are unofficial ports of Sonic games for various systems.
 * Somari is a pirated version of Sonic the Hedgehog for the Nintendo Entertainment System. However, rather than starring Sonic, the game features a character named "Somari", who is essentially Nintendo's mascot Mario wearing Miles "Tails" Prower's shoes.
 * Sonic CD DS is a proof-of-concept demo of Sonic CD for the Nintendo DS created by Simon "Stealth" Thomley. The port was created during the development of Christian Whitehead's remaster of Sonic CD; it is a native port written specifically for the DS hardware, and allows the player to play as Sonic, Tails or Knuckles.
 * Sonic the Hedgehog GBA is an unofficial port of Sonic the Hedgehog created by Simon Thomley for the Game Boy Advance. Created as a response to the poor reception of Sonic the Hedgehog Genesis (the official port of the game released by Sega), this version was developed by reverse-engineering the game to run on the Game Boy Advance; it additionally features the options to play as Tails or Knuckles.
 * Sonic the Hedgehog PC is an unofficial port of Sonic the Hedgehog (2006) for Microsoft Windows powered by Unity. Development began in 2015, and a demo was released in 2017.
 * Sonic Chaos is a remake of the 8-bit 1993 game of the same name. It features 16-bit graphics, as well as new game mechanics and boss fights.

Mods and ROM hacks
The following are all modified versions of existing Sonic games, created using special programs and utilities.
 * Unleashed Project is a mod of Sonic Generations developed by Team Unleashed that consists of modders Dario FF, S0LV0, ChimeraReiax, and MilesGBOY that ports most of the daytime stages from Sonic Unleashed. The mod additionally features new textures and shading techniques designed to mimic those featured in Sonic Unleashed, and a revamped hub world.
 * Sonic the Hedgehog Megamix is a total conversion mod of Sonic the Hedgehog developed by Team Megamix. The modified game features redesigned levels and multiple playable characters, each with unique abilities. Originally created on Sega Genesis hardware, Sonic the Hedgehog Megamix was eventually moved to the Sega CD in order to take advantage of the system's improved storage and CD audio capabilities.
 * Super Mario Generations is a mod of Sonic Generations developed by Daku Neko that replaces characters with those from the Mario series, and alters some of the sound and graphical effects of the game to make it more close to that of Mario. It is notable for making an appearance in the modding section of Guinness World Records 2017: Gamer's Edition.
 * Sonic Boom is a mod of Sonic the Hedgehog 2 which features new graphics, gameplay components, and music. Despite its title, the mod has nothing to do with the TV series of the same name. Sonic Boom is known for its intense difficulty and large amount of bosses.
 * Metal Sonic Hyperdrive is a heavy modification of Sonic the Hedgehog featuring Metal Sonic as the main character, as well as completely redesigned zones and new music.
 * Knuckles in Sonic 1 is a hack of Sonic the Hedgehog created by Simon "Stealth" Thomley which replaces Sonic with Knuckles the Echidna, complete with his moveset and sprites from Sonic & Knuckles.
 * Sonic 1 Boomed is a hack of Sonic the Hedgehog that implements Sonic's redesign from the Sonic Boom animated series, and additionally gives Sonic voice clips that play when the player simply jumps or collects rings. The hack was created as a joke to respond to the poor reception of Sonic Boom: Rise of Lyric.
 * Sonic 3 Complete is a hack of Sonic 3 & Knuckles which aims to provide a more improved version of Sonic the Hedgehog 3, with intent to make it closer to the original vision of the game. Several major changes are present, with the "Flying Battery" stage moved to its originally intended spot, and the Sonic & Knuckles title screen is reworked as a cutscene to bridge the transition from Sonic 3 stages to Sonic & Knuckles.
 * Sonic 2 Retro Remix is a large-scale hack of Sonic the Hedgehog 2. This hack features completely redesigned zones and requires the player to collect Chaos Emeralds in order to proceed through the game. Players must fulfill certain missions and objectives in order to collect emeralds, in a vein akin to Super Mario 64. 
 * Sonic 2 XL is a hack of Sonic the Hedgehog 2 that replaces the game's golden rings with onion rings that cause Sonic to become morbidly obese over time. The primary challenge of the hack is to collect as few rings as possible.
 * The S Factor: Sonia and Silver is a work-in-progress multi-level hack of Sonic the Hedgehog which centers around Sonia the Hedgehog, Sonic's sister who appeared in the TV series Sonic Underground, and Silver the Hedgehog, a time-traveling, psychokinetic hedgehog who first appeared in 2006's Sonic the Hedgehog, who each have unique abilities.
 * Yoshi in Sonic the Hedgehog 2 is a hack of Sonic the Hedgehog 2 that replaces Sonic with Yoshi, complete with his abilities from Yoshi's Island.
 * Sonic 2 Long Version is a hack of Sonic the Hedgehog 2 that restores four previously scrapped levels.
 * An unofficial Hebrew translation of Sonic the Hedgehog was released in 2017.
 * Sonic 3D Blast: Director's Cut is a hack of the Genesis version of Sonic 3D Blast released by the game's lead programmer, Jon Burton, in 2017. It features improved controls and gameplay additions not seen in the original version, such as a level editor, a password save system, time attack challenges, and the ability to transform into Super Sonic.

Film and animation

 * Sonic is a live-action/computer-animated 2013 short film written and directed by filmmaker Eddie Lebron, produced by Blue Core Studios and intended to be a prequel to the original video game. Jaleel White, who provided Sonic's voice for DIC Entertainment's cartoons, reprised his role, and numerous internet personalities make appearances. Lebron hoped the film would lead to a deal with Sega for an official feature-length Sonic film. Yuji Naka, lead programmer of the original Sonic video games, called the film "awesome."