“SEGA has announced Sonic 4: Episode I. It is, as GameSpot reports, a 2D downloadable game with 3D visuals.

The announcement is part of the Project Needlemouse build up SEGA has been pushing since last September 2009. “Needlemouse” refers to Sonic’s codename when the game that would become Sonic The Hedgehog was initially being pitched.

While teasing this Project Needlemouse project, SEGA has stated that the game is a return to Sonic’s 2D roots and that the blue hedgehog will be the only playable character.

The game will pick up after Sonic & Knucles, but, as “Episode I” indicates, this is a new story arc.”

Project Needlemouse Is… Sonic 4, Episode I (via Kotaku)