This past Saturday, during the South by Southwest Festival, Sega announced that Sonic will be coming back to the consoles this summer in Sonic Mania Plus. This is largely the same game as last summer's hit, Sonic Mania, but it comes with a couple new additions, like two new Sonic character deep cuts.
If you haven't picked up the game just yet and are interested in it, you're probably safe waiting until this summer when Sonic Mania Plus drops. The game adds a new "Encore Mode" that will offer plays a chance to play through same levels from the campaign, but remixed in new and interesting ways. Sega has also stated that there will be some visual tweaks applied in "Encore," but didn't state what that means, exactly. Along with the new mode, players can play through everything using either the standard roster of Sonic, Tails, and Knuckles, or as the new characters, Mighty the Armadillo and Ray the Flying Squirrel, which are taken from the 1993 arcade game, SegaSonic the Hedgehog.
As opposed to the digital-only release of Sonic Mania, there will be a physical edition of Sonic Mania Plus available to pick up. If you already own Sonic Mania, then don't worry; Sega will release some DLC for the game that will add all the content from Sonic Mania Plus, though no word on when that will happen or how much it will be.
Sonic Mania Plus is out Summer 2018 on the PlayStation 4, Xbox One, and Nintendo Switch. Two player couch co-op is supported in the campaign.