Sonic the Hedeghog: Outburst Theory, is a Sonic fangame made in the RPG Maker 2003 engine. The game is still, however, in early development. The game occurs before Sonic Rush, and after Shadow the Hedeghog.
Sonic the Hedeghog - No info.
Miles "Tails" Prower - No info.
Knuckles the Echinda - No info.
Amy Rose - No info.
Cream the Rabbit - No info.
Shadow the Hedeghog - No info.
Rogue the Bat - No info.
During Sonic's 19th birthday at the end of his vacation, Tails, Sonic's best friend, holds a party for him. But soon Eggman, who has seen a 5 year absence, crashes the party and shows off his newly found "Outburst Emeralds". Sonic must race to save the world from Eggman once again and find out the secrets of the Outburst Emeralds!
The game was originally concepted in around 2007-2008.