This last Saturday (July 22, 2017) at San Diego Comic Con, SEGA have announced that Special Stages will be in the upcoming Sonic Mania.
This was told to fans at the wildly popular Sonic Mania: Behind the Scenes panel, which had some new insight from Takashi Iizuka (head of Sonic Team), Christian Whitehead (developer for Sonic Mania), Simon Thomley (programmer), Tom Fry (artist), and Tee Lopes (composer), all of whom are working on Sonic Mania at the moment.
Moderated by Aaron Webber, who is the social media manager for Sonic, the panelists discussed the road to development behind the new game, prior to the release date of August 15, 2017. Other highlights from the panel included background on the origins of the game, anecdotes about the development process, the art behind the game, and additional details of the Sonic Mania vinyl, which you can preorder over here.
Sonic Mania will release for PlayStation 4, Nintendo Switch, Xbox One, and PC on August 15, 2017, with both a regular and limited edition.