The Franchise timeline of Sonic the Hedgehog is listed chronologically, and presents the universe, games, and the events which are listed in relation to the fictional universe based on the Sonic the Hedgehog series.
Note: Comics, books, and television shows are bolded, while games are italicized.
Early 1991: Rad Mobile, an arcade racing game published by SEGA, is released. Oddly enough, the game featured a little Sonic the Hedgehog air freshener which hung from the rear mirror. It was Sonic's first ever appearance in a game, predating even the first title of his own series.
January 20: Digi-Log Conversation: Sonic Adventure Original Sound Track, CD of the original musics of Sonic Adventure, launches in Japan.
July 15:Sonic Adventure: Limited Edition, an incomplete version of the American translation of the game, starts to be distributed. This version is only incomplete from having its internet capabilities removed, when compared to the full version.
Sega and Nintendo announce a joint-venture spin-off sports game starring Mario and Sonic the Hedgehog together in the same official video game for the very first time. This game is Mario & Sonic at the Olympic Games, an Olympic games being made for the 2008 Olympics in Beijing, China. This marks the first time that Sonic and Mario meet head-to-head in an official video game.
June 23: Sega and Sonic Team were celebrating Sonic's 20th Anniversary, and they launched Sonic's 20th Anniversary Blowout Sale. They included 11 Sonic games up to the 50% off for a limited time only; exclusively on the Xbox Live Arcade, PlayStation Network and Microsoft Windows. Also, the ESRB had an E for Everyone rating with Comic Mischief and Mild Violence.
June 23 - July 12: The demo version of Sonic Generations was released for the Xbox Live Arcade and PlayStation Network. It had 20 days to play it, and exclusively, it featured Classic Sonic's Green Hill Zone gameplay.
July 18: Sega and Sonic Team made a videoclip called Sonic's 20th Anniversary: Through the Ages, where it features the history of his games and they launched an all-new official website: www.sonicthehedgehog.com.
August 31:Sonic CD for the Sega Mega-CD returns! And it's announced that is coming this holiday exclusively on the Xbox Live Arcade, PlayStation Network, Android, Windows Phone 7 and iPhone / iPod Touch / iPad.
October 18: The second demo version of Sonic Generations was released for the Xbox Live Arcade and PlayStation Network. And now, it features Classic and Modern Sonic's Green Hill Zone gameplay; with the results screen at the end of the act, and Omochao on the loading screen. It was exclusively released in Europe.
October 25: The second demo version of Sonic Generations was exclusively released for the PlayStation Network in North America.
November 1: Sonic Generations is released for the Xbox 360 and PlayStation 3.
November 3:Sonic Generations is also released for Microsoft Windows.
November 15:Mario & Sonic at the London 2012 Olympic Games is released for the Wii.
November 22:Sonic Generations is released for the Nintendo 3DS.
December 14:Sonic CD is re-released for the Xbox Live Arcade and Android.
December 15:Sonic CD is re-released for the iPhone / iPod Touch / iPad.
December 20:Sonic CD is re-released for the PlayStation Network.
December 28: The wait is over! Sonic The Hedgehog 4: Episode II is finally here! And is announced that is going to be released in 2012. Exclusively for the Xbox Live Arcade, PlayStation Network, Android, Windows Phone 7 and iPhone / iPod Touch / iPad. This time, Sonic must unite with his best friend Tails in his new adventure, and Sonic's greatest rival, Metal Sonic, makes his return.
January 19:Sonic CD is re-released for Windows Phone 7.
January 27: The demo version of Mario & Sonic at the London 2012 Olympic Games was released for the Nintendo 3DS. The demo featured only 5 olympic events in 5 rounds with different playable characters. The events were: shooting, soccer, trampoline, swimming and cycling.
April 5: While Sega and Sonic Team got the release dates of Sonic The Hedgehog 4: Episode II, Sega and Sonic Team announced an extra game to unlock: Sonic The Hedgehog 4: Episode Metal. This game features Metal Sonic as the only playable character, the levels where Metal Sonic can be playable are exclusively the stages from Sonic The Hedgehog 4: Episode I and the players must discover the rebirth of Metal Sonic.
October 2:Sonic Adventure 2 is re-released for the PlayStation Network.
October 5:Sonic Adventure 2 is re-released for the Xbox Live Arcade.
Sonic Adventure 2 has changed the rating from the ESRB. In the Sega Dreamcast and Nintendo GameCube consoles, it had an E rating; and it contained: Violence in the Dreamcast console and Mild Lyrics and Violence in the GameCube console. But now, the game has an E10+ rating, and it contains: Mild Cartoon Violence and Mild Lyrics.
October 18:Sonic Jump (2012) videogame is released for the iPhone / iPod Touch / iPad.
November 2:Disney's Wreck-It Ralph is released in theatres. Having Sonic and Dr. Eggman making cameos in the film (in which Roger Craig Smith voiced Sonic only). Until for this, Wreck-It Ralph is set to join Sonic, his friends and the Sega All-Stars in Sonic & All-Stars Racing Transformed. (Along with Danica Patrick).
November 18: Sonic & All-Stars Racing Transformed is released for the Xbox 360, PlayStation 3 and Wii U. The Wii U is released too.
April 25:Sonic Athletics is released in Japan as an arcade game. Where 8 players must run fast just like they're pretending they're on the Olympic Games. And the game features 8 playable characters. The characters are: