Sonic Before the Sequel

Sonic Before the Sequel (abbreviated Sonic BTS) is a fan game created by LakeFeperd that serves as a interquel between Sonic the Hedgehog 1 and Sonic the Hedgehog 2. The player goes through numerous zones and alternates between Sonic, who wants to stop Dr. Eggman from launching the Death Egg, and Tails, who tries to keep up with Sonic and eventually teams up with him. During SAGE 2012, an update that included graphical improvements, an original soundtrack, and a bonus boss fight if you reach the good ending, was released.

This series of fan games made by LakeFeperd continued with a sequel, Sonic After the Sequel, and an interquel, Sonic Before the Sequel Aftermath (which formed into a different fan game, Sonic Chrono Adventure).