According to a user on the official SEGA forums, former Sonic 4 Brand Manager Ken Balough confirmed that Sonic 4 had a third episode planned, but it was cancelled. He has in the past hinted that a third episode was planned but this is the first time anyone associated with the project has come out and said that the series was to be a trilogy and that the third part was scrapped. Continue reading UPDATE: Sonic 4 Episode 3 Was Planned, Then Cancelled