And then there were six.
Chemical Plant Zone has been confirmed for Sonic Mania, joining Green Hill, Stardust Speedway, Flying Battery, Studiopolis and Mirage Saloon. Short videos of Act 1 and 2 are both below. Game Informer are the ones who originally shared the news. Venture Beat says that SEGA is teasing Act 2 having a “surprise ending”.
However, that was not all that we got. It seems Venture Beat also made a mistake with an image upload: